I just bought a 1995 F150 4x4 Ext. cab 5.8L about a month ago. It's only got 71,000 miles on it and I noticed a miss at higher rpm's. I looked and realized that the plugs/wires/cap/rotor were still factory equipment, so i replaced them, the wires are 8.8mm Accel w/ 500 ohms per foot resistance, Double platinum plugs, factory spec cap/rotor. Oh, yeah, a K&N was also installed. Amazing difference in performance, but with it running better the miss is standing out more too.... I don't know if I would call it a "miss" but that's the only way I can describe it. As it's running out in 1st gear, upper RPM's, it sort of sputters/hesitates, then after that it shifts and it's gone.... I am probably going to try running in 1st gear to maybe try to isolate where it's coming from, but I was also reading about similar problems in other forums about the cat. conv. maybe falling apart. It runs fantastic from idol to mid-range, but mid to upper is where I'm getting frustrated. Any help would be great.

 

Have you tried a coil? It could be breakdown due to the higher RPM, they are relatively cheap. I would try one next assuming you've pulled codes and there are none.

Cheers,
Popa Tim

 

Coil is a good suggestion for only a 15 dollar fix max.

If your haveing exhaust problems, thats also a good start.

Take that cat out if your in a non emissions state, or put an aftermarket one in if you need to meet emissions. =)

 

I appreciate the suggestions... I haven't done anything yet, but I have noticed that the idle keeps getting rougher the more I drive it. Haven't had a service light come on, but I'm going to pull codes this week. I also noticed that my idler pulley is a little worn and when I went to get a new one, the parts store listed 3 or 4 different pulleys for different options, but none of them were the same size or style, so I will probably have to go to ford to look for the right one. Is there a way to test the coil to see if it's bad? It wouldn't surprise me if it was bad as much sitting as this truck seems to have done (mileage wise) and it seems like electrical is the first thing to go when they aren't driven much. I'll post some photos soon, it's a sharp truck. I don't know if there is a problem with the exhaust or not, was just reading other forums with problems like mine and thought that may be an issue, but the truck sounds fine, just sounds like an internal backfire when I stomp the gas. I'll post more after I get some things looked at. Thanks.

 

Try looking for a vacuum leak.