2005 Grand prix gtp stock it hesitates to accelerate, sometimes car feels very slow. Sometimes it acts very normal and is a rocket. I changed plugs wires... just tired of throwing money at the car. I even had the PCM updated at the dealership. I did notice that problem seems to go away when I restart the car sometimes.
Another way to explain issue is say I'm at a light. I press throttle 1/4 of the way, sometimes it accelerates very slow. When the car acts normal it squeals the tires a bit.
I do see that two members fixed the issue somewhat with an aftermarket PCM tune. Any advice is greatly appreciated as this is making me go crazy.
