I have a 2001 f150 xlt and it has this miss that we cannot figure out. I have repalced all the coilpacks when we put in the new motor. I also put some new ngk plugs in at the same time. Ran great for a day then back to crap. We hooked a scanner up to it and got a o2 sensor 1 bank 1 code, a fuel system lean code and a random cylinder misfire code. So I went to the junkyard and grabbed the mass air meter out of the truck I got the motor out of it only had 42k on it and stuck it in truck ran great for about and hour then back again. We replaced the o2 sensor nothin still runs like crap. It has a serious miss when it shifts into overdrive and is running at crusing speeds,if you turn overdrive off it doesn't miss anymore. My only other thought is a PCM. We checked the EGR its working fine injectors are pulsing fine. I am at a loss and getting very frustrated. Does anyone know where the pcm is on a 2001 f150 I am goint to go to the junkyard and yank the one out of my 40k donar truck. Any other sugestions or advice would be appriciated. Thanks

 

Replace the spark plugs with Motorcrafts.

Fix the vacuum leak.

 

We checked for vaccum leaks there are none. It ran like this with the old motor in it with a blown headgasket. My buddy who works for ford said to try replacing the ecu. We hooked a scanner up to it tonight fuel system lean was the only code after driving it for a week like that. Can anyone tell me where the ecu is?

 

Sigh.....

 

Its not the ECU .
What were the STFT readings? If you don't know what that means go back to your Ford buddy and if he doesn't know get a new Ford buddy

 

I know what STFT means. I don't remember what the readings were can anyone tell me the range they are supposed to be in? So you guys are thinking it sounds more like an o2 problem?

 

Took off body to ground and clean it and cleand the ground from the alternator to the firewall drove it 100 miles and proablem solved I will keep everyone updated if it comes back