Hey guys need some help..... I have a 2010 HHR SS with the GM performance upgrade and i can be rolling at like 30 or 35 and hit the gas and before the upgrade the car would catch and take off... now it lags so bad unless i take my foot off the gas and then hit it again the car just lags... and this is with getting no low traction messages and there are no codes at all .... also if i put it in launch mode and it does the same thing, I am at a lose here with no codes I am not sure where to look for a problem and before i take it back to the dealership that did the upgrade I figured I check here to see if anyone has had something like this happen to them...

 

Do you mean the GMTU (the dealer installed turbo upgrade) or the G85 performance package?

Any chance the car has been tampered with improved by a tuner?

 

I have the GMTU. And no the car was a one owner car and I have all the paperwork on everything that has been done to the car from the day it was purchased till I bought it from them

 

How long has the GMTU been installed ? When did this lag start happening ? Auto or 5 speed ?
Many years ago there were a lot of issues with the GMTU install and the lower Tmap sensor wiring rubbing on the AC compressor. That’s where I would look.
There are several threads about this in the archives. You’ll have to do a Search.

 

I got it installed in Feb of this year..the lag seemed to be there from the start and its an auto ....thank you the info at least now i have a direction to look in

 

If you got it installed in February, why didn’t you take it back to the dealer that did the work ? Sounds like it’s their problem to resolve.
FYI. . The automatics were more likely to have the rubbing sensor problem. Their engines actual sit a slight bit more to the front of the engine bay. That puts the AC compressor closer to the lower charge pipe and the Tmap sensor.

 

Have you looked at fuel pressure?

 

Here's what I did with my lower sensor.
https://www.chevyhhr.net/forums/how-...ive-way-62943/

Hasn't given me any problems.

 

Odd, this sounds identical and in the same week. https://www.chevyhhr.net/forums/hhr-...flicked-67067/

 

One has the GMTU. The other does not.
Looks like 2 different problems.