I recently (May 2017) bought my 2007 Cobalt SS/SC. I didn't start having problems until a few months after purchase. I would randomly get ENG PWR REDUCED on the display and the car would run at 30% power. It is still doing this. I have done research and tried many different things yet still have the problem. I have replaced the throttle body, PCM, and accelerator pedal with no luck. I am suspecting it is the engine wiring harness. The problem I am running into now is I really do not want to examine every single wire in the harness or replace the harness completely because I cannot afford a new one at this time. Has anyone else had this problem? Any information on this topic would be helpful because at this point its just getting dangerous. Half the time I drive the car it chugs when I release the accelerator pedal (to about 400rpms) and other times I get little response, erratic response, or no response at all.