Cobalt Check Engine + Reduced Power: Throttle Body Issues?

Had a similar issue with my 2006 Chevy Malibu. After some basic DIY experience working on cars, I've learned these symptoms aren't always what they seem. Initially thought it was the throttle body too, but turned out to be the accelerator pedal module causing the reduced engine power and putting the car into limp mode. The engine idling was really rough before the fix. Took it to a shop after my attempts at cleaning the throttle body didn't help. Total repair cost was 265 for the new pedal module and programming. Much cheaper than replacing the whole throttle body assembly. The problem never came back and fuel efficiency actually improved a bit after the fix. What specific error codes are you getting? Have you noticed any changes in the pedal response or engine behavior before the check engine light came on? This info would help narrow down if you're dealing with the same issue.

Thanks for sharing your experience. Had my last service at 11704 KM and started noticing the response delay right after. Getting error code P2135, and yes, the pedal feels different, less responsive than usual. The throttle sensor readings seem off based on the scanner, and the engine idling gets really rough, especially when cold. Definitely seeing similar symptoms to what you described with the limp mode kicking in occasionally. Good to know about the pedal module being a potential culprit, that's a much better replacement cost than what I was quoted for the throttle body assembly. Did you need any special programming when you got the pedal module replaced?

Yep, your symptoms sound exactly like what I dealt with on my Malibu. That P2135 code is tricky, while it points to the throttle position sensor, the root cause isn't always the throttle body itself. The response delay and rough idle match what I experienced perfectly. Regarding the programming, absolutely needed it. The pedal module has to be calibrated to communicate properly with the throttle sensor and engine control module. The shop had to use their diagnostic tool to program it, which was included in that €265 total I mentioned. The fuel efficiency improvement was a nice bonus after the fix, went from burning extra gas with the rough idle to running much smoother. If your throttle sensor readings are off like mine were, there's a good chance the pedal module is the actual problem versus a complete throttle body failure. Quick tip from my experience, get the air intake system checked while they're at it. Mine had some buildup that was contributing to the rough idle, and cleaning that out along with the pedal module replacement made a huge difference in how the engine runs.

Thanks for the detailed info. After comparing our situations, I'm definitely leaning towards checking the pedal module first. Just called around and found a shop that can do the programming, they quoted me €290 for parts and labor, which sounds about right based on your experience. Going to bring it in tomorrow and have them check the air intake system like you suggested while they're working on it. Really hoping this solves both the check engine light and the rough idle issues. The reduced engine power and limp mode situations are getting pretty annoying, especially during my work commute. Will update on whether the pedal module fixes everything. Should be a lot cheaper than replacing the whole throttle body, and if it improves fuel efficiency like in your case, even better. Thanks again for helping me avoid potentially replacing the wrong part.