PITSTOP: ROUGH IDLE AFTER COLD START ON 3.3L GDI ENGINE - When addressing a customer complaint of rough idle, which occurs only on the first start of the day and lasts for 30-45 seconds, check for the possibility of poor injector performance in a particular cylinder. This concern may feel like a misfire, however, it is not an emissions or catalyst damaging misfire and it does not typically trigger any DTC(s). To diagnose this concern, go to KDS ? Data Analysis ? Engine and monitor for Current Misfire Counts on all 6 cylinders, during the first cold start in the morning, to assist in determining which cylinder is responsible for the rough idle condition. Replace only the injector for the affected cylinder. To verify the repair, recheck again after an overnight cold soak to make sure the rough idle condition is no longer present.
