Hi all need some help on a baffling problem. Wee have a 2003 Monte Carlo SS. Been a great car tell now. It is not supercharged has about 82k in miles.
What it does is after driving, then stopping it refuse to idle, or run. There are no codes or check engine lite on. But if you hold to around 3500 rpms, and owed brake it. Then drive it fast 70 to 80 mph it goes away and will run and idle again. About myself, 35 yes. Retired master auto tech. So I know my way around tell this. No codes at all. Also tried unplugging a lot oof sender's the mass air flow unplugged will let it idle and run normaly. Need some good feed back here for I am baffled.

 

If the unplugged MAF sensor allows it to run and idle normally, my first suggestion would be to try another MAF sensor. Usually they throw a code when they are bad, but it could also be something to do with the wiring.

 

Forgot to add, when you take the MAF sensor off, get yourself a can of MAF sensor cleaner, fairly cheap at any auto store, this may solve your problem with a quick spray and let it air dry, be sure not to touch the thin hair in the center of the MAF as they are easy to break and will definitely require you to get a new one.

They are pricey to buy new, so I suggest picking a used one up at a wreckers with a warranty, they usually give 60 or 90 days and you should be good to go, if that is the problem, but it sure sounds like it

 

Perhaps it is something as simple as your "idle air control" valve. (IAC)

 

possibly a bad vacuum line....those wont bring up codes and can make them run like crap