Quick vehicle issue history:
- Engine would shake badly when idling after long drive almost as though the car wanted to turn off and would get a strong gas smell. Would only get the gas smell when it would shake. Also noticed that the temp gauge reading would go above 210 when shaking and would drop once it stopped. This would trigger the Stabilitrak/Traction Control to come on. CEL would come on and would get P0171 code and forget the other code. Therefore, I replaced the air filter, MAF, and cleaned/relearned throttle body even replaced the gas cap and since then the Stabilitrak issue stopped.
- Engine would still shake after long drive during idle but not as rough would get CEL for HO2S Slow Response Bank 1 Sensor 1 but did not pay attention to the temp gauge. Therefore, I replaced both upstream oxygen sensors and no more CEL for sensor.