Last Friday I was on the way to an out of town meeting with my Eco and went through a road construction zone in the dark. I got a piece of metal in the sidewall of the tire and called roadside for assistance. They changed the tire and I got directions through OnStar to the nearest Chevy dealer. After the hour wait for them to arrive, I started my car and it ran rough for a few seconds and as I throttled the engine, it smoothed right out but the "Service Engine" light came on. When I got to the dealership, they replaced the tire (221.11 ouch!) and told me that there were two codes in the History but they were showing "cleared."- One was for 'Lean Condition" and the other was for "Boost Sensor Performance." They told me they could not find anything so I left. The light was still on and didn't go out until the next day but the car ran fine. On Tuesday of this week, the light came back on but the car is running fine. I have an appointment at the dealership that I bought it at next Tuesday. Any ideas or similar experiences?