MY 97 ford 4.6 f-150 has had a rough idle and a hesitation ever since i bought it used a year and a half ago. when i got it it had 28.000 miles on it. and know it has about 51.000 miles on it! and ever since it has had a rough idle at times. when you would pull up to a red light it would start running rough like it was going to quit? and when you would pull out it would hesitate i have had it back to FORD 4 or 5 times for this and they would say the diagnostic machine said it was okay! and i just give up and just figured that it was normal for these new type engines. i have spent over a $100.00 on fuel injector and combustion chamber cleaners? and they none seem to help! so it got a little warm here the other day and i got under my truck looking around and the fuel filter caught my eye. and i said to myself this thing probally needs changed? so i did! the old one you could not hardly even blow threw it! it was pretty clogged! i put my new filter on that i got at wal-mart for about $7.00 and my baby runs as smooth as silk now! (no rough idle and no hesitation) after all this time and money i spent and what ford paid the dealer to check it over a simple $7.00 FRAM fuel filter was the cure! now if i could get rid of the pinging i would be a very happy man?

 

I had mine changed just a couple of weeks ago and the old one was fine. I've got almost 70,000 miles on it. However, I too had rough idle, and it ran rough while accelerating during driving. Ended up buying the Ford 9mm plug wires and now it runs great!
Got the transmission filter changed today, no difference. Thinking of getting the B&M electronic shift kit.

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97 F-150 S/C 4x4 ORP XLT 4.6 K&N , Flowmaster w/dual tailpipes, Bosch+4 plugs,MSD 8.5 wires,Superchip.Patriot fiberglass toneau cover, Westin chrome step bars.
Kenwood 4011 stereo, Rockford 150a1 amp, Profile electronic crossover, and 2 10" JBL's.