everyonce in a while in my base cobalt when i start her up the revs go from 600 to 1500 like 4 or 5 times. This only happens on occasions. Is this normal?

 

any more info? There's a lot that can cause that. If you're throwing a code then it's probably a bum 02 sensor, if not then you could probably use a new fuel filter or some injector cleaner.

Whatever it is, it's a/f related problem... if a problem at all. Mine doesn't really do that but if it's common with the cars then it could just be some start-up procedure the bcm has.

One thing I urge everyone to do... If nothing else call gm and speak to a tech on the phone. Just be sure to ask specifically or they're going to want you to bring the car in...

 

Well mine does that... although not quite as harshly... ranging from 600-900 RPMs really jumpy but only with the A/C on!

 

no engine codes at all.. it's only happend to me like 4 times since i've owned the car. When i started to notice the weird idle it was about a month ago.

 

take it to your dealership i had my dad fix mine for me there is a bulliten for the ss/sc not sure about base models. Mine used to do that though.

 

My base coupe does the same thing... sometimes it's worse, sometimes i barely notice it. Having the A/C on aggravates the situation as well... I have to call the dealer tomorrow... might find out if there is anything wrong with it doing that, or if it's normal.

Scott

 

same here mine didnt throw a cel but thanx to these guys and gals i got it fixed

 

My source at GM says there is a cal fix for this that went to the dealers in June. The stage kit cals already had the fix in them. Go to the dealer and ask for a cal update to fix the problem.

 

Just go to the dealership and get your cpu reflashed. Or you can get Stage 1 or 2 and the fix is included in there as well. All set!

 

I just had this fixed myself on my SS/SC on Wednesday. Its a low idle problem where the brakes and/or AC are taking too much from the engine and then the idle (which is already low to begin with) drops lower and jumps to compensate and drops and jumps. The reflash is through the Powertrain Control Module and raises the idle to about 900 RPM +/- a few. Its a warranty item so besides the inconvenience of having to go to the dealer it won't cost you anything at all.

 

I've been having this problem for like a week now... But it doesnt occur on a cold start (like when the cars been off for 4-5 hours, it'll start normally). It only occurs when I drive the car, turn it off and than try starting it again. One time I think I had the a/c on, and it felt as if the car was gonna shut off. Do I have to go to gm to get this fixed, or is it possible I can fix this myself?

 

Its a reflash of the computer, so unless you have the software and access to the hardware you can't do much on your own. Bring it to the dealer. I dropped my car off at 8 and they finished the reflash after a full diagnostic in about 2 hours. Yeah it was a PITA but no my engine is running like it shoulda been running when I bought it.

 

same here.. it only happens after the car has been running then i try to restart it and it happens.. I don't know if they have a reflash for us 2.2 cobalts.

 

Aha, so that's what it is. We have this problem on our LS coupe only it happens when braking and the A/C is on, it feels like the car is about to die on us.