I have had this car for about 5 months. It started dying all the time when i stopped so i had engine light checked. The mass air flow and IAC valve were replaced. It ran good for a while and is still doing same thing. I changed the MAF again and its still doing the same thing. Does anyone know what could cause this

There could be several possible reasons for your Chevy Tahoe to start and then die immediately. Here are a few things you can check:

1. Fuel system: Make sure you have enough fuel in the tank and that the fuel pump is functioning properly. Check the fuel filter as well.
2. Ignition system: Check the ignition system, including the spark plugs, wires, distributor, and ignition coil. Make sure they are all working properly.
3. Idle air control valve: The idle air control valve (IAC) helps regulate the engine's idle speed. If it's faulty or clogged, it can cause the engine to stall. Check the IAC valve and clean or replace it if necessary.
4. Mass air flow sensor: The mass air flow (MAF) sensor measures the amount of air entering the engine and helps determine the correct fuel-to-air ratio. If it's dirty or faulty, it can cause the engine to stall. Clean or replace the MAF sensor if needed.
5. Security system: If your Chevy Tahoe has a factory-installed security system, it may be malfunctioning and preventing the engine from starting. Try resetting the security system and see if that helps.

If you're unable to diagnose and fix the problem on your own, it may be best to take your vehicle to a trusted mechanic or dealership for further diagnosis and repair.

Possible Mass air flow sensor , disconnect wiring from sensor see if it runs better, just make sure you have a diagnostic tool to hand in-case any engine management light come on dash.

Dirty IAC - idle air control valve , throttle plate dirty - carbon , vacuum leak ! mass air flow sensor ! Is the check engine light on ? How to clean throttle body and Idle air control valve iac

try running a couple cans of fuel injector cleaner through the tank-Denny

yea id definately try cleaning ur throttle body 1st. My 03 1500hd had the exact same bad idle after my battery went bad it would die at lights unless i kept foot on gas i cleaned throttle body runs perfect now took 30min cost 8$ for cleaner at autozone and theres how to videos on you tube

IAC idler air control valve bumps up the RPM and doesnot let the engine to die, how ever if its not the IAC then Ide be looking at the TEMP sensor which migh have a fair line crack or may be the MAF mass air flow sensor might be bad, seems like the engine is not geting air, check the air filter first.

There are couple of things I would check out that would cause this problem.

1. The Mass Air Flow Sensor. It measures how much air is going into the engine. Should be located on top of air filter box.

2. The air tube that goes from the Mass Air Flow Sensor to the throttle body. Check for leaks that would bypass air from going through the Mass Air Flow Sensor.

3. The Throttle Position Sensor. Located on the throttle body. This tells the computer what position the butterfly plate is on the throttle body. You control this plate with the gas pedal..

1 Inspect EGR Valve EGR Valve Sticking Open/Leaking. 2 Inspect Idle Air Control Valve IAC Valve Sticking or Faulty. 3 Inspect Mass Air Flow Sensor Damaged, Loose, or Faulty Mass Air Flow Sensor or Circuit.

I would check your MAF and the IAC.  Try cleaning your Mass Air Flow sensor which is in the tube that takes air from the air filter to the throttle body (you will see that it is plugged in).  Clean it with some cleaner that says it's safe for a MAF.  If it's not that and what I am leaning towards would be your IAC valve.  The idle air control valve is located on your throttle body and is normally attached with two screws.  I would start with the MAF just because it's cheaper but I'm leaning towards the IAC.  Let me know if you have any other questions.  Thanks for an honest rating and for using FixYa!

I suspect you have an idle circuit issue. When the thottle is closed, the throttle valve is almost closed (like 95%). The linkage on the throttle body is against the hard stop.
SO, when idling you need a way to let enough air into the engine to maintain an idle speed. The IAC, Idle Air Control valve is the way you do that and the engine computer controls the rate of air flow.
Sometimes it gets plugged up so you can clean it with a little carb cleaner. Might have to take it apart.
Also, you have a MAF, Mass Air Flow sensor that tells the computer how much air is flowing through the air cleaner intake at any time. The sensor gets coated with varnish and vies a false reading. Clean it gently with carb cleaner and a toothbrush.
Other than that, I would go to an auto parts store that can run a computer scan for free to see if you have any fault codes stored. They will tell you next stpes.

I assume you 2.0L SPI engine & not Zetec.


Idle Air Control (IAC) Valve —2.0L SPI Removal

1. Disconnect the idle air control (IAC) valve electrical connector (air cleaner outlet tube removed for clarity).

1. Remove the IAC valve.

1. Remove and discard the IAC valve gasket.

Mass Air Flow (MAF) Sensor Removal

1. Remove the air cleaner outlet pipe.

1. Disconnect the mass air flow (MAF) sensor electrical connector.

1. Remove the MAF sensor.

clean element inside carefully


PS. A good running engine makes for a better running transmission