I have a 2000 Maxima with 55K miles. Lately the car hesitates when you first start out with the engine cold. You press down on the gas pedal and there is no response for a few seconds. After that the car runs normal. I just replaced all of the coils and plugs (engine was pinging badly) but this has had no effect on the hesitation sympton. I tried using Techtron injector cleaner to see if that would improve things but it did not. The engine throws a P0171 code (Right Bank running lead) from time to time. Maybe a clogged injecter? Any suggestions?