HEy guys, hope somebody can help me out

Almost everytime I start my cobalt (2.2) the RPM fluctuates between 1500 to 500 back and forth like 3-4 times before it goes back to normal. Does anybody know why it does thats bacuse I went to the dealer and I showed him my problem and the tech guy said well the computer isint reading any codes. I say **** the codes!!! If he sees there's an issue with the car, fix it.

Help me out guys!

 

Mine does that alot too, it has since I bought it....don't know why.

 

ive got the same issue, but ive got a k&n intake and 2.5 inch exhaust. i jsut deal with it, although it is annoying

 

Seems like a fairly common problem. I think I read somewhere they have a flash to fix the issue.

 

Mine does that too when I start it up and when I come to a stop it does that. My friends does it too. I think thats just how they are, I asked my uncle, he works at GM, and he hasnt heard anything bout them doing that so idk.

 

They have a flash that can fix your problem or atleast minimize it. My SS/SC did it but i got it reflashed and now it does it very rarely.

 

Dont know if cobalts have this, but if it was a stang it would be the IAC Valve(Idle Air Control valve) that would be sticking. Look into it.

 

No IAC on these, they are electronic throttle.

If you reset your computer a lot or remove your battery, it will probably be worse. When the fuel trims aren't learned I've noticed this happening more frequently on any trim Cobalt.

Also check your vacuum lines for anything disconnected or cracked.

 

I've got an 2007 ss/sc, and my revs bounce from 500-1500 and back like one to three times when i come to a stop....but ONLY when I have my air on. if I don't have my air on, no bouncing at all..

 

the flash will fix it mine did it all the time but after the flash it is a very rare occurence

 

Mine does it all the time, I dont know if to take it to the dealer though, I have Intake exhaust headers and d/p so dont know if my waranty will cover it now. Does anyone know how much they charge?

 

when i first had my gmpp intake and my dc sports cat abck put on mine did that but now it is running just fine plus i just got a new dp with a high flow cat

 

I have the clear image headers and d/p with high flow, at first i thought it just needed to break in but it still has the prob.

 

i had the same thing but i was leaking raditor fluid into my head. bad times.

 

Is there a code or reference that I can use at the dealer to get the reflash? I am heading in for an oil change today, so if they can do that at the same time it would be sweet. Mine did it for a little while and hasn't done it for a while. Does anyone know if the ECU just learns to control this issue or is a reflash the best bet? Just dont want it to start up if I get a reflash.