I have the same problem. Less than 500 miles. Dealer has had car for 14 of the last 22 days. No Codes set, pending or otherwise. Changed PCM, Changed plugs, several snapshots of Pcm when car is acting up and when its running fine. No disernable differences and No Help from GM Tech Support. Back bumper covered in soot.

 

To Lizhutch,

Sorry to hear you have the same thing going on. Very frustrating!!!
I've yet to hear back from GM on my declaration of a "Lemon"?
I'm approaching 3,000 miles on this car, and the matter doesn't go away by itself!
If anyone with this problem is interested in getting together to fight GM on this, please send me an E-Mail at jabrams800@comcast.net .
Thanks everyone!

jabr800

 

From jabr800 (Originator of this thread)

After turning over 3,000 miles on this 2009 Cobalt SS, with it's asthma problems, it seems to be starting to run better.
For the past 3 days, it runs right up to 260hp (on the performance display) when asked without skipping a beat anymore.
I can't figure out why. One thing a little different here in Central Florida now is that temperatures are about 15 degrees less then when I first got the car, andf there is less humidity in the air also!
Can't quite figure out the simple version of why it's running better. Let's see if it lasts?
Everyone else with problems, please keep me posted on how your vehicles are operating!

jabr800

 

From jabr800 (originator of the thread)

Just got the call from GM about my "Lemon" and they want to schedule a time to have their people look at the car for the last time.

Unfortunately, I can't get the car in for 3 weeks, but I will when I can!

More to follow gang!

Jabr800

 

Sorry to bump this, my 08 SS/TC is having a similar problem, it's very noticeable when I run through second gear. Car pulls well from about 2500 and then seems to fall on it's face at about 3500 to 4500 when it picks up again and pulls smoothly to redline. Definitely feels like something in the ecu is pulling power, doesn't feel like a misfire or a boost leak. Just rolled 700 miles on the odo so I'm just beginning to push the car a little and I noticed this today. Seems to happen with comp mode on and off.

The boost gauge holds steady at 15 psi throughout the pull. No CELs.

It definitely doesn't feel like something you would expect in a car capable of sub 6 second 0-60 times.

I haven't talked to the dealer yet because I'm not sure this is a problem. I'm going to keep an eye on it though.

jabr800, any updates on your situation?

 

From jabr800 (Originator of this thread)

I will be calling GM tomorrow, to set up an appt. at the Chevy dealer, hopefully in the next 14 days or so, with GM Tech Support from Detroit present.
The car has been running anywhere from perfect to AWFUL!!!!
I still can't determine a pattern to this problem.
Most recent series of "Huffing and Puffing", started after buying fuel.
It was a very high volume and quality fuel station, so I can't believe they are selling cheap gas, but the car runs badly again!

jabr800