hey everyone hope someone can help me out ive recently have had problems with my 1997 f150 4x4 with a 4.2l in it well its using too much gas has considerable loss of power idles rough like a misfire well to give more info about what ive done ive changed the o2 sensors the cam position sensor the computer i replaced the motor with a brand new one from jasper engines about 1000 miles ago the old one had major blowby and was wore out oh by the way it was doing it with the old motor in it too i have added performance parts like a cam a vortech supercharger jba headers a 70mm throttle body a 85mm maf meter 30#injectors a nice flowing exhaust system and a 255lph fuel pump i did my homework when it came to adding power oh just so anyone doesnt jump to conclusions about all the performance parts i added it ran great when i added them with the old engine better than a 4.6 or a 5.4l actually alot better i just cant seem to pinpoint the problem i have a scanner and checked it nothing wrong by the scanners diagnostics anyone out there have any solutions or just some helpful hints im all out of answers here need some help please

 

I seem to have the same problem as you, but unfortunately no one wants to take a stab at our problems.........off to ford I go

 

I've been having the same problem, not sure what it is, I've done all the checks and have the dealer stumped. I'm starting to wonder if its the pcm. Maybe it needs reprograming.

 

Tbone -
I'd start with new plugs and wires, if you haven't already done that.