I am working on the 97 F150 inline 6. The truck runs rich - checked and changed TPS sensor - ACT sensor - ECT sensor - spark plugs - STILL runs too rich.
Fuel pressure is 50 lbs -
Rough idle, misses bad after a few hours - change plugs and it runs ok? for a couple days and then fouls them out. ANY thoughts? Thanks, timbuk2

 

Have you given any thought to the O2 sensors? Could be that the ECM isnt processing the signals from the O2 sensors correctly. Possible bad ECM. It is also possible that the IAC motor is stuck. Wouldnt cost you anything but time and a can of cleaner to clean the IAC ports and plunger. Worth a shot if you ask me.

Later

Dale

 

I think your fuel pressure might be to high
37-40 lbs
mitch

 

I thought that too but I dont know anything about Ford's fuel injection. I used to be a hard core Chevy man and the 30-40 range was acceptable on most GM vehicles. You may need to call your local Ford dealer to see if they will tell you proper fuel pressure stats before you go much further.

Later

Dale

 

Just throw many at it? I thought that was the regular Porsche attitude for my 928 - thats why I do my own work...
I didn't know it applies to my work truck.....too.
Replaced the fuel regulator, pressure is 45lbs. Cleaned/replaced all the sending units. Good vacuum. Changed to a new spare coil - Love my Ford! Still no workie...
Thanks Dale, Mitch, this thing is slightly confusing - Oh yeah - the check engine light is on at all times too, maybe I should rotate the air in the tires? Har Har - - -
Michael