OK so Im wondering if I am having fuel related problems. Heres the deal.

My car is a 99GT with 4:10s, X-Pipe, No Cats, Stage 2 Clutch, CAI, Flowmasters, NGK Tr6s.

The car has always spark knocked unless I run premium fuel. I have a new fuel filter and plugs. The other day I was driving her hard and had a buddy following on his bike. I noticed at higher speeds around 4000 or so the car seemed to bog kinda like it was loosing fuel. This was only past 4000RPMS If I shifted up and lowered the RPMS it didnt seem like it was starving for fuel. My buddy said every time I shifted there was a good bit of black smoke comming out. I know a little is normal since I have no cats. Any way to tell if its fuel pump or not? I used to have a fuel pressure gauge installed and it was around 40 at idle, and went to around 55 or so under WOT. But when I let off the gas it would drop almost to 0. Then come back up to where it needed to be, that however could have been a gauge error. When I changed the fuel filter it was pretty dirty, Im guessing if it was that dirty the screen on the fuel pump is probably pretty dirty as well and may be blocking fuel which is causing the fuel pump to burn up. I dont really want to have to replace it if I dont need it. Any other symptoms to look for? If I do replace it it will be with a SVT Focus pump since I kinda do need more fuel for my nitrous.

 

Doesn't really sound like a Fuel Pump issue..Fuel Pumps on these cars usually just die with little warning. Is your car sending out any Codes?(check engine light)

 

Yea I have a CEL but from a oxy sensor with a cut in a wire that is shorting out. Its a rear ox sensor though. Its causing several codes bc that wire and the egr share the same 12 volt.

 

id suggest cleaning ur injectors.

 

I cleaned them when I replaced my intake manifold around 6 months ago. Ill do it again though and see.