OK, here I am at the end of my rope.
I have a modifed 95 f150 that i swaped heads, cam, gears, ported intake, exhaust.
the moter is a stock 302 (not punched out)
with the addion of the cam, I Ford MASS AIR KIT.
heres my problem, when i accerate the egning stops reving at 4100 rpms. I acts like the computer hits a rev limit. will spuder and pop (sounds like a backfire)
I also get codes 41,91 from the computer (lean left & right O2 sensors)

heres what I have tried, changed computer, changed MASS air metter, changed control module, installed an ajustable fuel presure reg (set to 45 with vacuume line off), tested and swaped TPS sensor, tested and swaped O2 sensor, reinstalled the SD computer
(with the SD computer, the engine wouldnt idel right, but would run all the way to rev limit of 6250.) with trying all the above nothing changed how the engine proformed. I inspected the wiring harrness of both a 93 mustang and my trucks stock harrness, the only differance was that the mustang was wired for SEFI, and my truck is bach fire EFI, and provisions for the mass air metter. the rest of the wire harrness is the same between the two cars.

Ford tech service wont give me any help on this, there anser was to return the kit for a refund.
any help ya can give me would be a live saver, i'm almost readdy to sell the damn truck.
thanks

 

Yuor kit SHOULD have contained a harness overlay that with a splice or two converted you to SEFI. Mass air probably won't work with batch fire.