Car does not always have full power (acceleration)

Hi Guys,

I recently picked up another GTP that was already modded.

98 White GTP,

1.9 Ratio Roller Rockers
105# Springs
Ported Supercharger
SLP Headers
Flowmaster Mufflers
U bend delete
No resonator
Cat (unsure what kind)
02 sim
MSD Plug Wires
Fuel Pump Hotwire Kit
DHP Performance Programmed PCM
3.4” pulley:
Autolite 104s @ .052-.054” gap (Just changed)
K&N filter attached to stock intake tubing (came like that)

When I really get on it, sometimes it feels like it has full power and other times it feels as if the supercharger belt was off.

I replaced the belt with a new 060 gatorback belt. I don't believe that the belt is slipping since the boost gauge reads 8 PSI regardless if I feel the power loss or not.

Where should I begin to look to start troubleshooting?

Thanks

Andy

I wonder if your experiencing knock Retard the times when you have loss of accelleration. Do you have any way to get it scanned to watch you KR values?

Yeah, I posted on a local forum and that's what people think.

A local guy has a scanner so I think we're gonna give that a try.

I had what you describe also only not very noticable. Mine had a sticky injector that made the car run and idle good, but over fueled one cylinder. I'm thinking the PCM got a rich signal from the O2 sensor and leaned back all cylinders causeing KR. I pulled my plugs and found one with a thick coating of carbon that smelled like gas. I replaced the corrosponding fuel injector and all has been good since.

Maybe pull your plugs and have a look. You could even ohm check your injectors. If you come to find out one of your injectors is bad, send me a PM, I have a bunch of used ones I have aquired I could sell you one for cheap.