Hello, I'm Rodney. I am an Air Force veteran and I drive a Black, 2007 Cobalt SS. My Cobalt SS has a rough idle issue that I need help with. I bought the car in March of this year and it had the issue then (the young Navy girl that I bought it from didn't know what the cause was). I read somewhere on the internet about a CAI (I think that means Cool Air Intake). Maybe that's what the issue is with my car, I don't know. I just had a recall repair done on my fuel tank, fuel pump and a fuel pipe. The car will idle when I first start it up now (it didn't before). Once I drive it, it will not idle on it's own (I have to keep up the rpm's or it will die out). When it shuts off, it takes 3 to 5 minutes of constant tries to start it up again (that has been a serious issue with other drivers behind you in traffic)
I really need some help here, if anyone can shed some light on what's going on, I would appreciate it very much. I can do some mechanical work, although I am not a mechanic.

Thanks in advance,
Rodney

 

Well usually to what I've seen cleaning the throttle body helps with the idle, give that a shot

 

RodG7 - Since you other thread is more of an introduction, I will be replying to this one about your issue instead Just so you know.

When you cleaned it did you move the throttle plate at all ? If so Im pretty sure you need to get it re-calibrated by gm.

Secondly I think the pcv is located on the intake mani I am not 100% so maybe wait for an LSJ'er to chime in on the exact location.

 

Yeah the PCV valve on the LSJ's are located inside of the Intake Manifold.

 

Pardon my ignorance, but what is an LSJ?

Thanks for the advice. The rough idle issue is a little bit better (since cleaning the throttle body). It will sit and idle when I first start it up now. It didn't do that before. When I went to get a new PCV valve at the parts store, I was told that the PCV valve is not replaceable. The guy said that it may not have one at all. That really helped me out a lot (more confused for sure now). :-(

So now what do I do?

Rodney

 

LSJ is the supercharged 2.0L engine found in many Cobalt SS's in 2007.

The parts store guy is ignorant. It is replaceable, but he likely doesn't carry it. The main PCV valve sits inside of the intake manifold. You'd probably need to get a new one from a dealer if you want to replace it. I'd do a few other checks first though, since it's a more involved process to replace than other cars. If you take off the oil fill cap while idling, does the idle change? Or the dipstick?

 

You mention you have a cold air intake... inspect the couplers (& filter), and make sure they are installed properly, and snug.

Your rough idle can be a vac leak as well. Also, inspect the maf sensor. It may need to be cleaned.

Don't go throwing parts at it until you inspect everything first.

 

Okay, sorry for the delay. I had too much going on recently. I just went out and started my car and then I took the oil fill cap off and there was a lot of pressure under the fill cap. White smoke is coming out of the fill cap hole (not a lot, but it's like a small chimney). The car idled fine with the cap off. The car would shut off after about two minutes or so before the cap removal. With the cap off it kept idling fine.
What does all of that mean?

 

Seems like it could be a pcv issue.

 

I appreciate it. I think that's what my problem is with the car. I'm trying to find a line going into the intake (for my PCV valve) so that I can take it off and clean it out. I know what my weekend holds.

 

You won't find it. The port goes directly from the head to the intake manifold. The only way that is serviceable is to remove the IM.

 

Im

 

Check the pic.




May help out with you understanding where it is located!

Not very expensive at all from Crate engines online here