I have an 86 F150 5.0 fuel injected. Right now it is running like crap. I have replaced the EGR valve and sensor (plugged), the throttle position sensor and the intake air temperature sensor. It is timed and I have good fuel pressure. The problem is that it runs very, very rich, backfires through the intake, idles erratically at times and acceleration is very jerky with little to no power. I can't find any vacuum leaks, yet the problem persists. I have run it on an OBD and it comes up with these codes 22, 23, 31, 42, 72, and 73. I thought a knock sensor may have been to blame, but when I checked the voltage to it from the PCM it was only 1.9 volts. The Haynes said it should be about 5 volts. I am at a stand still, my only other diagnosis would be a faulty PCM.


Any Suggestions from anyone?

 

I would start with the tps. With it out of whack the comp thinks its running wide open and is pouring extra fuel in. Smack the housing a few times with a screw driver or tap it firmly with a hammer. It may fix its self.

 

I forgot to add that when it warms up it when it surges and hesitates the worst. What do you think?