I recently bought a 2004 grand prix gt2.. When starting the engine all the gauges max out and return to normal but that being said its also sluggish to start resulting in me having to give it gas to start it and/or to keep it running. I added some injector cleaner to a tank of gas that was 3/4 way full. I had filled the tank the day before. When j picked up the car it had 1/4 tank... Any suggestions would be appreciated, thanks![]()