My 2009 Cobalt has been a wonderful car but it recently developed a problem where the car would surge and buck. Check engine light came on and car went into "reduced power mode." I never had the code read but after some research, I found that Cobalts had a problem with the throttle body. The only fix is to replace the throttle body. Fairly inexpensive if you're handy with tools and do it yourself. Otherwise, the repair bill to have it done at a shop can run up to $500.

Unfortunately I never had the chance to replace the throttle body due to an accident that totaled the car, but from my research it seems that it was a good fix. The engine goes into "reduced power mode" when it senses a fault with the throttle body. This is to ensure the car doesn't take off on you like some other makes did.

If this happens to you, find a place to pull over and turn the car off and let it sit for a few minutes and then start it back up. Sometimes it will run fine the rest of the day or it may do it again immediately. I recommend going to www.partsgeek.com for the best price on a new throttle body.

Hope this helps.