None.
I have put about 3,500 miles on the car so far, including several long trips of 250 miles or more. The biggest (and practically only) problem I have had with the car is the loss of comfort on those longer trips... I have tried adjusting everything on the seat (even the lumbar) and it just seems hard to find a good comfortable spot in the car. Other than that, I love the great gas mileage (32) I have averaged between city and highway - well above what the car is rated to get on average. I love all the info the dash computer provides. Has great zip for a little 4 banger! Rides very smooth and quiet for a cheaper-end car. So far no mechanical problems, knock on wood.
We just encountered problems with sway bars and bushings at 42,000 miles on our 2007 Cobalt. Both were worn out and not covered by warranty, although both items affect steering performance. The shop wasn't able to purchase GM replacement parts as all dealers said they kept them in stock but were out - clearly showing this is an issue w/this year/model. All that being said, the repair including labor was under $200 using our local, small town mechanic. And, I love the car still -
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