The issue started with flashing check engine light and flashing hold light. When fault occurred the car would not shift into higher gear until vehicle was stopped and turned off for 15-20 seconds. The fault would occur while passing or climbing hills. Initial repair was computer reprogram and after 300 miles of driving fault came back. Next repair was ignition coil replacement = no change. Problem was determined to be a common Chevy Aveo problem of a bad head. Timing belt had never broken but the valves were not seating correctly and when the cam would turn the valve on the number 1 cylinder would move more sideways then up and down. Due to Chevy's decision to not take it upon themselves to repair their well known about faulty product, this will be the last GM product I will own.