Silverado Runs Better With Maf Unplugged

Back in mechanics class, we had this '03 GMC Jimmy (Chevy Blazer) who had a dead MAF, thing couldnt even move with it plugged in, you could turn over, it would run for 2 seconds and straight up die. This is so the engine will run, but usually at a reduced power rate so you can get home without needing a tow. Of course now there are more modern ways of testing a sensor such as with a multimeter or scan tool. So if it runs better with the MAF unplugged, it's a pretty good bet that's your problem. A 22mm socket is needed to remove the sensors. It is a single wire sealed connector that has a tan with black stripe lead. If it runs better with the MAF unplugged it invariable means a duff MAF. Have changed almost everything (complete tuneup} plus the throttle possession sensor. It is only held in by 3 rubber pins. Over a long period of time the higher combustion temperature can cause valve damage. -Cleaned the MAF's with MAF cleaner, still runs bad. The truck starts, idles, and revs normally and when accellarating slowly everything works just fine, but once you get past half throttle it falls on its face and acts like it has a clogged fuel filter or bad fuel pump. The air mass information is necessary for the engine control unit (ECU) to balance and deliver the correct fuel mass to the engine. Tell If You Really Need a Mass Air Flow. You could try a can of MAF cleaner which is only like $7-8 & if that doesn't work you might want to look into replacing it. I live close to my job so I don't really drive too much to get around. So, I replaced the MAF, with a used one, and plugged it in. The sensor element could get contaminated or damaged. His hands were always dirty, but the MAP sensor looks old. I had problems similar to yours, and found that the MAF sensor installed in my car was a knock off. Better idle with Mass Airflow Sensor unplugged. What tools do I need? Circuit Descriptions of the MAF Sensor Connector. Top 7 Symptoms of an Engine Running Rich #1 – Check Engine Light On. Normaly if you unplug your maf sensor from your ecu it should run a tad better to rougher depending on tons of things. bad maf, old rule of thumb if the car runs better with it unplugged or if you can tap on it and it stumbles or dies it is usually bad, id look into the maf sensor, could be a possibility Rons65stang 08-24-2012 06:37 PM. As soon as I plug the maf in it sputters and then eventually turns off. A bad MAF would throw a code. Granted, I wasn't wringing the car out with the MAF unplugged, but I did rev it up with part throttle to see what was going on. I have a 1997 chevy 1500 siverado with a 5. That is why your trans is shifting hard. If the engine runs better with the MAF disconnected, it is likely your MAF is not functioning. If you have a car with a Mass Air Flow sensor (looking at you, General Motors) these wastes of money are the worst. I ran mine without the MAF and it ran, but it did some RPM seeking when cruising. Now remove the entire airbox as one piece. The front sensor faired much better, but we're not leaving anything to change. CalPak sawed in half, ribbon cable runs to ZIF socket 1985 Stock FuelPump Relay on Drivers Side Engine bay Firewall 1985 Drivers Side Engine bay Firewall - mount points for "new" MAF Sensor and MAF Burn-off relays MAF Sensor and MAF burn-off relays from a '87 (left) and '89 (right) Fbody (Top View). From my experience with the 2. This is so the engine will run, but usually at a reduced power rate so you can get home without needing a tow. Plug it back indies immediately after start-up. put headgaskets, timing chain ect in. Chevrolet Silverado 1999-2006: How to Replace Knock Sensors. The reason the engine runs better with the MAF unplugged is because it is operating on the backup system; the Manifold Absolute Pressure (MAP) sensor. My car has 90000 miles. With a voltmeter, measure the reference voltage by touching the reference wire with the meter's positive lead and the negative lead to ground-black wire, which is at the connector's end coming from the computer. I have put 2 new ones on it, checked all the wiring and plugs to it. It was throwing MAF codes so I replaced the MAF with this one and it fixed the problem. Ok so I've been having some rough Idling problems recently. Odd GM programming, that's for sure. Unplug O2 sensor and leave it un plugged and run the car and let it warm up and see how it runs. Add Horsepower and Save Gas With a Performance Filter System: I'm going to tell you how to add horsepower and save gas with a Performance Filter System. C5 MAF sensor. For the biggest power gains we recommend running E85 fuel (for flex fuel equipped trucks), or regular 93 octane. You could even try starting it with the MAF failed in the tune or even unplugged to rule out a bad MAF. CalPak sawed in half, ribbon cable runs to ZIF socket 1985 Stock FuelPump Relay on Drivers Side Engine bay Firewall 1985 Drivers Side Engine bay Firewall - mount points for "new" MAF Sensor and MAF Burn-off relays MAF Sensor and MAF burn-off relays from a '87 (left) and '89 (right) Fbody (Top View). If your Silverado runs lean for too long, or during hard acceleration it can cause engine pinging or pre-detonation. Low power, lean conditions (cracked air intake tube) GM There is no better on-line training of how to troubleshoot automotive electrical and electronics systems anywhere! How to Clean. At the center of the MAF, is a very thin wire whose resistance increases as it goes up in temperature. I don't think there is a vacuum leak because again with the sensor unplugged it runs like a wet dream. My common sense would say it's a bad 02 sensor, but I'm a novice at tuning these. Technician B says that this indicates the PCM is defective. He said unplug the MAF sensor the next time it happens and see if it goes away. Unplug the electrical connector from the MAP sensor and turn the ignition key on, but do not start the engine. New PA Alternator back in the beginning. Left alone this can cause premature damage or catastrophic failure of your engine. The MAF sensor is very sensitive to vacuum leaks because it is measuring the amount of air coming into the engine, through the intake. Begin checking a vane-type MAF sensor by checking the voltage supply wire and the ground wire to the MAF module before checking the sensor voltage. Your car is going into safe mode and rev limiting you at 2500 rpm. Compare the most helpful customer reviews of the best rated products in our Automotive Replacement Mass Air Flow Sensors store. The maf itself isn't "larger" its just a different style maf The LS3/LS7 style maf fits in a larger housing 92mm or 102mm(4"). No difference when unplugged. The powertrain control module (PCM) uses the MAF sensor signal in order to provide the correct fuel delivery for a wide range of engine speeds and loads. 7 Truck 110000 miles, running sluggish, has a code 42. I got these 2 codes (p0172 and p0175) so i figured it was the MAF sensor. By continuing to use this site you consent to the use of cookies on your device as described in our cookie policy unless you have disabled them. Check the O2 sensor harness for shorts. Just because you unplug the MAF and it runs, doesn't mean it's the only thing bad. I live close to my job so I don't really drive too much to get around. Runs better when IAC. 2 to 6 is correct MAF reading for warmed up idle, remember it's calculated PCM looks at IAT and MAS (sensor frequency) to calculate the weight of the air in grams per/sec. Whether you transform your oil at a car dealership, in specialty operations, or in your very own garage, you will should establish just what kind is most effectively for your auto. My Nissan pathfinder starts and runs great when it's cold but after it gets to normal running temperature and you drive it then it starts skipping really bad and becomes hard to keep running I had it tested and it come up with the knock sensor and I just wanted to see have anyone else had that problem and did changing the knock sensor solve it. So I unplugged it. When you unplug the MAP sensor it puts the ECM in bypass or limp home mode. Another way you can check the EVR on many vehicles (not all) if you don't have a scan tool capable of PID manipulation is to do the following: Run a Key On Engine Running (KOER) self test, and have your vacuum gauge hooked to the vacuum line coming in to the EGR valve. With it unplugged, the ECU uses a default map and thats why it appears to be going better. So I put on a brand new MAP sensor. If you test the other leads associated with the MAF and you see another 5V reference and a return voltage those will be for the intake air temp. Here's what you can do if yours is idling rough. I have witnessed this on another car; when MAF disconnected, the engine rpm increased slightly and increased rpm made the engine seemed as though it was running better. We hope you enjoyed the article 2016 Chevy Silverado 1500 Programmer, Chips & Tuners | 5 Best Tuners & Chips to increase Mileage, Efficiency & Horsepower to its entire bits. An old air filter. Cam sensor possibly as well. Warning: If your check engine light is not already lit up when you try this test, unplugging the MAF sensor will cause it to. o2 sensor code 44 (lean) Replaced: coolant temp sensor, tps, map sensor, fuel filter, and o2 sensor. Disconnecting MAP sensor (wiring) makes engine run great. It runs the same when the knock sensor is unplugged, which makes me think the knock sensor isn't the culprit. It's regulated by the onboard computer, but the data has to come from the mass air flow sensor for Chevy Silverado. New PA Alternator back in the beginning. Now, before the chip I was only getting 13 MPG on a 2011 Tahoe. im using a 92 engine harness, with a 402 red label DME. Disconneting MAF makes the car run per the ECU programming rather than sensor feedbacks. She was no longer starved for fuel which, by the way, is why she ran better with the MAP sensor unplugged. It did idle rough but it made it down the road much better unplugged. I have the MAF fail freq high and low set to 0hz. When the engine is running, air passes through the MAF, which sends a voltage signal to the engine controller. The forester runs great now, no CEL, no rough idle. As a result, I suspect there is a fuel (or spark) issue on one cylinder. Air filter has nothing to do with it. The most basic test is to unplug the MAF while the engine is turned off, and then start it. If you think your Silverado MAP sensor is going bad, this How To Guide can help you test it. The tap-with-a-hammer test made the voltage reading increase on the digital multi-meter. I pulled air box and disconnected MAF to change headlight bulbs. Bad ground 43 ESC circuit failure Bad ESC module or wiring. The car runs rich at idling or lean when running. See if you can beg/borrow/steal a scan tool and read the temp sensor data. My car has an automatic transmission. Why does the engine run better when you unplug the egr solenoid on your 1991 gmc ck1500 5. well i replaced the MAF and the car still runs like crap: stuttering a little bit while accelerating, not idyling well. To add to the OP, driving with the MAF unplugged is really the ideal solution until you can fix it. We have a 2001 Tahoe doing this. I entered all 0s in the MAF table and have the MAF unplugged and its running great, so im assuming its running in SD mode I just want to confirm that it doesnt NEED to actually set P0101 code for SD mode. Re: 1999 Silverado running rough5. Watch the gauge closely while the test runs. You can drive it with the MAP unplugged for a while with no harm. With it unplugged, the ECU uses a default map and thats why it appears to be going better. Page 1 of 3: How to Test the GM MAF Sensor 4. Cleaned maf correctly (maf-specific spray and followed instructions. Which technician is correct?. If the ECM determines that the current load and throttle position are not consistent with the expected load and throttle position, DTC P0068 is set. Leave the MAF plugged in. It will run normal on occasion but only lasts about 45 seconds or so. but we're turning that off now anyway. We also carry filters, shocks, floor mats, and other useful service parts. The MAF may not be functioning properly but it will not send a CEL until it is dead. What could cause truck to run perfect when map sensor unplugged (2004 Chevrolet Silverado 2500) If i plug it in when it's running it will go dead like it runs out of gas And won't start back until I unplug it. 1990 bmw 325i (e30). When you unplug the MAP sensor it puts the ECM in bypass or limp home mode. Unplug the wiring to the sensor by hand. 2 to 6 is correct MAF reading for warmed up idle, remember it's calculated PCM looks at IAT and MAS (sensor frequency) to calculate the weight of the air in grams per/sec. 1999 - 2003 7. Older style meters used on fuel injection systems in the 1980s measured air volumetric flow, which worked fine but then you also needed a separate sensor to figure out how. Unplug sensor if it run better with out the sensor being plugged in the replace. I already unplugged it and it runs great so i am just curious. Granted, I wasn't wringing the car out with the MAF unplugged, but I did rev it up with part throttle to see what was going on. Chevrolet is hard to start or has trouble turning over; vehicle engine stalls soon after starting. Page 1 of 6: Symptoms of a BAD IAT Sensor. Trailer Running Light Fuse Location on a 2012 Ford F-250 Question: Hi, I have a 2012 Ford F250 with a 7-way connector in the bed of the truck as well as the factory installed 7-way. 3 LS engine It's one of the coils. So disconnect the MAP sensor first and she went into limp mode no power at all connect it back up and disconnect MAF sensor and she's much better more responsive. when i its plugged in, the car runs very badly, barely idles and eventually shuts off. I guarantee you wont even be able to tell. Whether you transform your oil at a car dealership, in specialty operations, or in your very own garage, you will should establish just what kind is most effectively for your auto. They designed it to use two injectors to even-out pressure drops in the fuel rail which would give smoother running at full throttle and high RPM. 15 reviews of Silverado Village Apartment Homes by ConAm Management "After posting on Yelp, the leak in my apartment bathroom has been fixed and ceiling panels have been replaced. Warning: If your check engine light is not already lit up when you try this test, unplugging the MAF sensor will cause it to. 1994 silverado dies when put in gear and push the accelerator. This is a painful process, but there is currently no other way. When the MAF sensor is unplugged, the engine runs better. Make sure there are no air-leaks from the MAF to the throttle body and also make sure your MAF sensor isn’t all clogged up (albeit a dirty MAF isn’t going to completely stop your fox from running). A 22mm socket is needed to remove the sensors. And have done a fuel pressure test, everything seems to check out. He may know. I've been dealing with it on my Camaro for the last couple of weeks. A small quantity of air entering the engine indicates deceleration or idle. Just be alert for these common symptoms: 1. GM and GMC. It was strange. Page 1 of 3: How to Test the GM MAF Sensor 4. Disco runs better without it so sod it. is my MAF junk, or fixable? i tried pulling codes but kept getting the code 55 (no code code). Just make sure to remove and clean the lower air filter box change the air filter and the snow screen which is located next to the battery where the air enters. It will run normal on occasion but only lasts about 45 seconds or so. when i unplug the MAF the p0172 code goes away and the code for the MAF appears. 3 LS engine It's one of the coils. And there’s no better way to keep your engine breathing right – and running great – than. I have replaced the Maf, no change. Will expose a sensor that's grossly out-of-whack, though. -So the maf company had me run some voltage tests that they feel seem out of range. )sensor is unplugged,or the vacuum (some had a vacuum line) to it is lost,the engine will not. Depending on your setup the gains are most attributed to the maf and its better tuning capabilities, not the larger housing unless your making high hp such as close to 500whp. If you do not have a smoke machine, you will need an alternative method for producing smoke, but please do not bring an open flame to the engine bay. It runs off a pre set program stored in the MEM Cal pac. If MAF was bad to run 18% lean you MAF would have to be in the 3. My common sense would say it's a bad 02 sensor, but I'm a novice at tuning these. To add to the OP, driving with the MAF unplugged is really the ideal solution until you can fix it. You can also just try unplugging the ECT. well i replaced the MAF and the car still runs like crap: stuttering a little bit while accelerating, not idyling well. But anything else this means? I cleaned the MAF sensor with spray MAF cleaner and no change. MAF sensor is located near the air filter housing as shown in the following picture. Normaly if you unplug your maf sensor from your ecu it should run a tad better to rougher depending on tons of things. It did idle rough but it made it down the road much better unplugged. If you run the car with the MAF unhooked & it runs better than with it hooked up, that's probably the issue. This will be easy to spot because the return voltage will be less than 5V (or better be). Now, before the chip I was only getting 13 MPG on a 2011 Tahoe. The car runs fine. Got a renault trafic at the moment, started having issues with throttle response, mainly when starting warm, tracked the issue down to the intake temp sensor wiring, repaired and swapped the MAF for a siemens one as it seemed to give a more accurate result, van worked fine for 2 days, then came back with same issue. Upon getting some CRC MAF cleaner, I removed my MAF and found a piece of dandelion fuzz stuck to the MAF 'sensor wire thingies'. Introduced in January 1995, it is a "clean sheet" design with only rod bearings, lifters, and bore spacing in common with the longstanding Chevrolet small block V8 that preceded it as the basis for GM small-block V8s. Hey Jack, I feel your pain! I am not sure how much help I can really be over email. This is a painful process, but there is currently no other way. My buddy is running the ls7 MAF which might be an option. Air filter has nothing to do with it. When you unplug the MAF the computer sees the failure and goes to a "backup plan" that smooths out the rough running (if the sensor was causing it). It's not going to affect how the car idles. And there's no better way to keep your engine breathing right - and running great - than ACDelco. When replacing Maf did not work, i started replacing other parts, main relay, ignition and engine control modules, camshaft position sensor, pulse sensor, i checked al the wiring for corroded connectors or damaged cables, found none. These always are blocked. Runs better when IAC. I started with the MAF sensor because that's what my problem sounds like after researching it here. prior to that with the maf plugged in the car would run 5seconds, drop rpms for 1 second, and repeat pretty consistently. I appreciate the help. If it still runs then likely the MAF is bad. I don't think there is a vacuum leak because again with the sensor unplugged it runs like a wet dream. See if you can beg/borrow/steal a scan tool and read the temp sensor data. Problems with mass air flow sensors are common in many cars, including BMW, GM, Volkswagen, Mazda, Toyota, Nissan and other brands. It's regulated by the onboard computer, but the data has to come from the mass air flow sensor for Chevy Silverado. Leave the MAF plugged in. This is important, as it allows your engine to regulate its performance and change the intake of air to keep your engine running in its best condition. No difference when unplugged. I have a 2003 tahoe z71 with a 5. Make to sure to check all the clamps on the intake system and PCV valve lines that none are cracked and leaking air into the system unaccounted for. Problems with mass air flow sensors are common in many cars, including BMW, GM, Volkswagen, Mazda, Toyota, Nissan and other brands. However i also tried running the car with the airflow meter unplugged, the problem dissappeared completely. Naturally, I thought the maf was bad, but when I swapped the maf (with a known good one) I have the same problem. The CEL will light will be on, it may run a little rich and get poor mpg. but we're turning that off now anyway. The car seems to have a rough idle and is running lean as well. Chevrolet Silverado 1999-2006: How to Replace Knock Sensors. By continuing to use this site you consent to the use of cookies on your device as described in our cookie policy unless you have disabled them. The engine runs unusually lean or rich idling. You either knocked a hose loose that is behind the MAF (allowing unmetered air to enter the throttle) or the MAF came unplugged. It did idle rough but it made it down the road much better unplugged. Odd GM programming, that's for sure. 1999 Chevy Silverado - Sluggish Acceleration? I'm wondering if there's a problem somewhere like bad intake sensors or something. A clean MAF sensor is a happy MAF sensor. Not sure if unplugging it before you start it will work, bit it's worth a try. But autozones read map sensor(had it unplugged it plugged in now before was scanner) tps low circuit, MAF threw one a few others he didn't show me much just said go have scanned by some place with better equipment haha. If that doesn't work check mass airflow sensor. i have a code for mass air flow sensor it runs better if unplugged but my question is can i drive with it unplugged for like a week until i get the cash or should i just leave it plugged up. No, it will run with a proper mixture. Re: Engine runs better with MAP sensor unplugged? There are two trouble codes associated with the MAP sensor. I happened to unplug the MAF and it actually runs! Enough to get me a 3 hours drive home thank God. What happens if the MAP sensor is bad on my 1991 2500 454 TBI Suburban? What effects will be noticed. Note: The use of "oiled" air filters can cause the MAF to become dirty if the filter is over-oiled. It is very obvious that we are running rich in this example, by a pretty steady amount right? Well, lets look at the MAF table breakdown, and decide what we need to do. Older style meters used on fuel injection systems in the 1980s measured air volumetric flow, which worked fine but then you also needed a separate sensor to figure out how. I don't think its the torque converter, going into neutral doesn't seem to make a difference when it starts to stall, and will only stall occasionally when stopped after warmed u. I ran mine without the MAF and it ran, but it did some RPM seeking when cruising. If your car is running better with maf unplugged then a) ur maf was bad b) it was getting bad reading c) u have a leak in ur intake track and or pulling in unmetered air. Major changes included: Full-size trucks don't change with the wind, so when an all-new example hits the streets, it's a pretty big deal. I don't have a fuel pressure testing kit but hope to locate one to borrow. its an LS3/LS7 card style maf. Once in a while we may encounter a total failure of a MAF sensor, one that is, perhaps, short circuited or internally open. I've been dealing with it on my Camaro for the last couple of weeks. In most cases, this code is not very difficult to diagnose. Car won’t stay alive! Won’t start with the mag plugged in. Any of those and maybe more can cause the MAF calculations to be noticed as implausible by the ECM. i get it home. Power is pretty much gone. Sounds like the MAF plug based on your description. Want To Put It In My 88 Silverado That Has A 5. Your Mass Air Flow (MAF) Sensor is a piece of technology within your engine which tells your car's computer how much air is entering the engine. With it unplugged it goes into safe mode and will run decently untill 2500 rpm at wich point it will hit a rev limiter. It idles low and doesn't run well but it runs. A mass (air) flow sensor (MAF) is a sensor used to determine the mass flow rate of air entering a fuel-injected internal combustion engine. Next unplug the MAF sensor from the wire harness. Sensor output toggles up and down, the car runs better. When the 02 is plugged in, my car idles a little rough, runs rich, and has a slight "miss" to it. Once I plug the MAF sensor back in, car starts to struggle again. I then unplug the MAP and it runs okay again (until finally it dies after a few minutes) Here's a list of what I've checked and replaced: Checked for vacuum leaks-none found Removed Cat. Back in mechanics class, we had this '03 GMC Jimmy (Chevy Blazer) who had a dead MAF, thing couldnt even move with it plugged in, you could turn over, it would run for 2 seconds and straight up die. I unplugged my maf the other day to spray maf cleaner on it. Running a 2 bar setup to accommodate a blower or turbo is the chief reason most people switch. It's not going to affect how the car idles. Another way you can check the EVR on many vehicles (not all) if you don't have a scan tool capable of PID manipulation is to do the following: Run a Key On Engine Running (KOER) self test, and have your vacuum gauge hooked to the vacuum line coming in to the EGR valve. Of course now there are more modern ways of testing a sensor such as with a multimeter or scan tool. I've been dealing with it on my Camaro for the last couple of weeks. (better than I remember) and runs fine on the highway, no loss of power, no black smoke, really seems to. The trick is to discover where the MAF curve needs to be set at. None of that comes close to The added preformnce I got with the maf best 200. For me it's usually timing issues. Ensure the MAF-1 tune (with the new MAF table you worked on above) is flashed into your truck, fire up the truck, clear the fuel trims and begin logging. Cam sensor possibly as well. If I roll the throttle on super slow it wants to die and if you play with the throttle it will rev up and sounds normal but it doesn't want to idle. Conditions for Setting the DTCs The ECM detects that the actual airflow rate is greater than the calculated airflow. 94 Chevy Truck surges at idle in gear, loss of power under accel? I just bought a 1994 K2500 w/ 5. Will this clear by itself with time, or should I disconnect battery? Will I lose settings by doing this? Wll the truck run crappy for a while? Thanks for any help. In this article I'll show you how to do it in a step-by-step fashion that will either condemn the mass air flow (MAF) sensor as BAD or exonerate it. Runs rough idle-2200rpm. I have witnessed this on another car; when MAF disconnected, the engine rpm increased slightly and increased rpm made the engine seemed as though it was running better. But id suggest you try and find another maf unit and see if that fixes your problem if not there could be something wrong with your fire or fuel mixture or your ecu settings. I started with the MAF sensor because that's what my problem sounds like after researching it here. Better idle with Mass Airflow Sensor unplugged. Hint: Use a descriptive title for your new message If you're looking for help and want to draw people in who can assist you, use a descriptive subject title when posting your message. The engine will run better without it but will produce more smog. This is a discussion on Better idle with Mass Airflow Sensor unplugged within the General Help forums, part of the LSx Technical Help Section category; I have been chasing down an idle problem and decided to unplug the MAF to see if it would run. Running a 2 bar setup to accommodate a blower or turbo is the chief reason most people switch. True backfiring is almost always a mechanical timing problem. This will be easy to spot because the return voltage will be less than 5V (or better be). For the biggest power gains we recommend running E85 fuel (for flex fuel equipped trucks), or regular 93 octane. With it unplugged it goes into safe mode and will run decently untill 2500 rpm at wich point it will hit a rev limiter. no code returned and vehicle runs great. 87 silverado 350 tbi only runs with map disconnected News: 73-87chevytrucks. Unplug the wiring to the sensor by hand. My problem is this: It is running super rich and it has a hunting idle. )sensor is unplugged,or the vacuum (some had a vacuum line) to it is lost,the engine will not. 1 suspect, no difference. The canned tunes were better than stock but the custom tune from lew (06montess) just sort of smoothed everything out and made it a bit stronger and smoother. If the engine runs better with the MAF disconnected, it is likely your MAF is not functioning. It would either just flood out and die or not even start. It may not run perfectly as a car with a lot of miles needs some fuel trim correction. Just because you unplug the MAF and it runs, doesn't mean it's the only thing bad. Your solution is going to be a newer MAF and a translator. I've been dealing with it on my Camaro for the last couple of weeks. A MAF sensor needs to run properly because the ECU needs information about the amount of air in the engine. It runs off a pre set program stored in the MEM Cal pac. Granted, I wasn't wringing the car out with the MAF unplugged, but I did rev it up with part throttle to see what was going on. If it runs better with the MAF diconnected, the MAF is probably at fault. I unplugged the sensor tonight and after a couple minutes it idled smoothly, not rich, and no miss. The MAF sensor is very sensitive to vacuum leaks because it is measuring the amount of air coming into the engine, through the intake. However, very few N/A cars will benefit from it, since you're not going to run out of MAF unless your making obscene power or your cam's so choppy the MAF is freaking out. however i believe the MAF is bad. With the MAF unplugged the car is running in speed density mode, which just says (as I understand it - which isn't much) at this rpm, there's this much air flowing and you need this much fuel, instead of going off of actual air flow. I tried to test the sensor from youtube and web info. The 2008 Chevrolet Silverado has 431 problems & defects reported by Silverado owners. This issue I am going to explain the MAP (Manifold Absolute Pressure), MAF (Mass Air Flow), and IAT (Intake Air Temperature sensors and their functions. The engine runs fine when cold but as it warms up it starts to "surge" at idle and when you come to a stop it acts like it wants to stall then it grabs. The mass air flow (MAF) sensor is an air flow meter that measures the amount of air entering the engine. There are various designs of MAF sensors, but the most common by far is the hot wire MAF sensor. Chevy Silverado 6. I have a 2003 tahoe z71 with a 5. took a little while to figure it out but the maf was bad and caused the plugs to foul. This can cause major damage to the sensor.