Guys,

I havent been able to find a solution to this problem anywhere and was hoping someone here could give some helpful input...

I have a 96GT with a '00 GT motor and over the last few weeks have had a crazy problem that has made the car run like crap to the point where I cant drive it anymore. The cur bucks like crazy, in any gear. If I try to give it gas it just shudders and bucks - kinda like hitting the rev limiter. I pulled the codes on it and got the following...

P0320 - Ignition speed sensor
P0171 - Bank 1 lean
P0174 - Bank 2 lean
P0141 - 02 sensor heater circuit

The car is lowered and the h-pipe had taken a beating over the alst couple of years, but I took the car to my shop and fixed the exhaust leak that had occured. After fixing the leak, the car ran fine for a little while, but slowly reverted back to the crazy bucking Im experiencing now. It was weird at first because the car would run fine when cold but as it heated up the bucking would start. I tried replacing the crank position sensor but with the new sensor the car would just drop rpms and die while in the middle of driving, so I put the old one back on and still have the bucking present. I think the P0141 is a sensor for the REAR passenger 02, but my rear 02 are both brand new. My MILs are worn, but I dont think bad MILs would cause a driveability problem.The car also has a new fuel filter, so the bucking isnt from a clogged fuel filter either.

I dont know what to do, my local dealer (Galpin Ford) wont do any engine diagonstics cause I have aftermarket mods. Has anyone had similar problems or does anyone know what is wrong with my car? Please help, any input would be appreciated.

Thanks,
Eric
__________________
Eric
96 Pacific Green Metallic GT 5spd
'00 GT 4.6 L SOHC motor
Mobil 1, Flowmaster American Thunder Catback, FRPP 3.73s, BBK Hi-Flo H-Pipe, FMS shorty headers, Steeda pullies, King Cobra Clutch
246.5 RWHP 279.3 RWTQ

Mods since Dyno:
Accufab 70mm TB,C&L 80mm Mass Air Kit, Plasma Booster, Steeda T/A @ 14*

Suspension Mods:
Tokico shocks/struts, Eibach springs, Cobra R 17x9's w 275/40/17 Kumhos D&D C/C plates

 

ok i just had the same problem you did. i was running lean on both also and exceeding the rpm/speed thingy which is a duh... dont worry about that one. anyways i was running lean because my fuel injectors were gettin clogged and all it took was a cleaning which any local shop or you can do. the bucking may be form a broken motor mount which i just had to replace on mine cuz mine was making like a knocking sound. i dont know your defintion of a buck.