My daughter's 2004 Chevy Cavalier has been dieing when you take your foot off the gas pedal. It starts up fine?

sounds like the air flow sensor or a hole in the air intake

hi Rachel, you probably did no longer point out what engine determination you have on your Cougar: the two.0L 4 cylinder or the two.5L DOHC V-6 engine? (There are multiple issues on each and each engine which will reason your difficulty) If yours has the two.0L (4 cylinder) hazard is the difficulty is a chop up PCV hose elbow. extra: @ keith p, including your self! there is not any adjustment in this engine of ANY type, the PCM (Powertrain administration module) has finished administration of the finished engine! extra observe: The engine will nonetheless idle @ approximately 500-550 RPM with the IAC unplugged! it is how the minimum air fee is adjusted!

either the maf, or map sensor might be going bad, or if it has a idle air control (i.a.c.) it might be on the fritz, get it dyno'd , they check for stuff like that

Put in a new air filter & put some fuel injection cleaner in the gas.

tell your daughter to get the fuel filter changed. it sounds like there is an restriction in the fuel line.

Time for a shop, either the throttle is dirty and needs cleaning or the idle controller has failed.

http://www.bgfindashop.com/bgservices/fuelair.htm

Don W, AND darvosix BOTH HAVE GOOD ANSWERS......... IT COULD ALSO BE THE THROTTLE POSITION SENSOR........ CAN BE DIAGNOSED FOR FREE AT " AUTO ZONE "............MOST OF THE PARTS MENTIONED CAN BE TESTED.............IT COULD ALSO BE A VACUUM LEAK, BROKEN, CRACKED, OR DISCONNECTED VACUUM HOSE, OR INTAKE MANIFOLD GASKET LEAK............CHECK WITH A VACUUM GAGE..........SHOULD READ AROUND 20 ..............

I think it has to do with the fuel system somewhere!

fuel pump or filter