1997 Ford F-150 Rough Idle

SDANDERSON

MEMBER
1997 FORD F-150
V8
4WD
AUTOMATIC
195,000 MILES

This truck has begun to run rough and will die at stop lights or when idling. It drives perfectly when you are on the gas and keep it above 1.5 RPM's. I have just tried running 44K Injector Cleaner through it, so far no change. The mechanic changed the temp sensor, checked for vacuum leaks, and was unable to get a read from the computer. He is convinced it is an emissions system problem and not an engine problem. The Check Engine light has been on for over a year but our mechanic has said that it is not related to the current issue. This truck had a complete tune-up ~10,000 miles ago. Could it be the Catalytic Converter?

Any help is much appreciated.

1 Reply

2CARPRO JACK

MECHANIC
11,533 POSTS

If you suspect teh cats. Loosen theexhaust pipes before thecats (back of manifolds) and drive it, it will be loud but if the cats are plugged it will run ok. Check all fuses with atest light, you need to get the codes out of the computer to see what is wrong with it. If itis missing, the PCM will let you know which cylinder, it may even just be lean and missing due to low fuel pressure, but the PCM needs to be scanned