New to the form tryied doing to search but came up empty handed !! This is my sons car its a 2005 gtp awhile ago he said the car had no accerlation power and the cel would flicker or blink on and off when you hard throttle or roll into it ! Local parts store gave me a po300 code so i cleaned the mass air and changed plugs and plug wires car still does it !! When he bought it he said car did it on test drive the dealership said it was a fuel cap issue and replaced the cap ............ now few months later car doing it again kinda leads me to the think maybe a weak fuel pump ???? Where would i find on the motor to plug in a gauge to check fuel pressure ? What kinda fuel pressure should i see ?? If you hold the car at 3,000 rpms in park it sounds fine no misfire to me but if your driving the car and get on it it kinda falls on its face and shutters doesnt really pick up and go , why i was leaning towards a weak fuel pump ..... from what ive read 2005 does not have a fuel filter outside the tank ??? Car has right at 90,000 miles on it now and is also bone stock !! thanx guys