2006 Chevrolet Cobalt

Engine Performance problem
2006 Chevy Cobalt 4 cyl Two Wheel Drive Automatic 80000 miles

When I am sitting at stop sign or stop light the car idles lower than 1 and it dies sometimes, but you can start it back up. The panel that shows gas and all that will go up and down when try to start it and it will keep going up and down even when not started for about 20 seconds. Now it has recently started dying when driving sometimes. I don't know if it could be fuel pump or the idle air control valve. Just did oil change, changed air filter, and changed the fuel filter. I would donate money if I had it but just got fired due to illness two weeks ago and really need help with figuring this out before I spend all my money.
May 20, 2010.

Try cleaning out the idle air control valve and test the throttle position sensor and manifold absolute pressure sensor also check the fuel pressure if its within specs.

May 21, 2010.
I wanted to thank you for helping me. I will get all this checked tomorrow. I was gonna check the thing about the air Idle control and wasn't sure how. Thank you again!

May 22, 2010.