Recently bought a 98 F150 XLT 5.4L 173,000 miles for very cheap. had a misfire on #4 and sounds like a farm tractor... exhaust leak probably on both sides. Removed, cleaned and replaced all gaskets for the throttle body assy, replace dpfe valve, pcv connector assembly hose, all 8 COP's ... i spilled coolant on entire passenger side removing throttle body so figure may as well do them all. All plug except #8 if that is the driver rear.. she wouldnt budge, didnt want to break it. #8 wasnt a problem so figure it be fine. After all that it ran pretty rough. Checked the gap on the last new plug i had... stupid me... trusted NAPA. pregapped at .045 not the .054 i needed. regapped entire passenger side, then realized i did not connect the wire harness to the dpfe.... Dumb again. So i plugged it in, said screw the driver side, wanted to try it. Runs better, but... shifts decent 1-3. When shifting into 4th, city speed or high speed, engine boggs down, very little power and kicks the whole truck shifting.

additional on the bogging... once in 4th, if remaining a speed for example of 35, keeping foot lightly on gas to do so, then wanting to accelerate so push on gas more, it bogs real bad and there is no power, but if let go of has and reapply she flies! But still will kick and bog when going back into 4th.

Long post bit trying to be as informative as possible. right mow main concern is the bogging and kickinf whe going into 4th. any suggestions?

 

What brand plugs and cops did you use? Did you use dielectric grease?

 

unfortunately i use autolite plugs, and ena cop's. truck shook so darn much when i bought it, only paid 600. didnt want to spend a fortune. it no longer shakes at any speed, so i "assumed" i got lucky. But like i said in the post the plugs were gapped at .045 and didnt check them. i regapped 123 and 4 .... all on passenger side, bit didnt regap the driver side. Yes i used dialectric grease and again when i regapped the 4 on passenger side.

 

You need to get that plug out of #8. If it strips out, you can fix that with a Timesert.

Use only MOTORCRAFT plugs, and either Motorcraft, Visteon, or Delphi cops. Get those Autolites out of there, they won't last.

 

This is what will fix the bogging and shift kick problem? I drove it today and realized it does not matter what speed i am going, any hill is a engine bogger. No power whatsoever.

 

Shot in the dark here. Drive it around after dark and make it bog, then get out and look at the cats. They may be starting to plug. Running with the exhaust leaks will cause it to throw a lean code and richen up the A/F ratio. Again just a shot in the dark.

Good luck

 

Possible dirty injectors - throw some Techron in the gas.

Kicking and bogging right after a shift into overdrive is usually an ignition issue. It could possibly be the EGR valve opening too far. However, more gas forcing a downshift to 3rd will usually clear it up.