I have a 01 Saleen 281sc it was previously tuned by prodyno before I purchased the car and ran fine. Over the past few months it has started to have a issue when you wind the gears out . it started acting like a spark issue so I replaced the plugs with ngk tr6 gapped at 32 , also replaced the cops with new motorcraft units. Seemed better but no perfect afterwards. I have also replaced the fuel filter , checked for vac leaks etc. Put my scanner on it and saw the o2 sensors are cycling and the fuel pressure at idle was normal , but if you rev it up it jumps to 51 psi and the a/f guage reading is dropping to around 9.5 . I have an appt. to get it retuned but would love to hear opinions. The only mods done since Ive had are cats were removed, cai from stock maf to fender, and had supercharger rebuilt due to bearings making noise , no porting just rebulit and rotors recoated Done by Joker.