BamaTony

I have a 2000 Ford F-150 4X4 5.4 LITRE and when I get up to around 55 maybe 60 mph it'll start jerking some, so I was wondering what would cause that? Could it be a fuel filter, need a tune up, or I know for a fact my rear pinion seal is bad. Could the rear pinion seal be causing it to jerk when i hit certain speeds? It has plenty of power otherwise, so I'm thinking it doesn't need a tune up?

Thanks,

Tony

Mr B

I had a similar problem with my 97 4.2L. I looked at every possible part of the ignition system and researched multiple forums. The general opinion was either the fuel filter ($20 part $10 tool) or the plugs and wires ($35 Bosch platinum splitfire plugs and $70 Motorcraft wires). I chose to follow this advise and the problem not only dissapeared, but my mpg went up noticeably. The part that bothered me though, was that throughout the whole ordeal I never had any codes. However, that was also 20,000 miles ago so I guess you can say it's fixed. Good luck!

billpru

That's a pretty broad area of possibilities. If you have an automatic it could be the torque converter locking and unlocking. Check the rpm's when it occurs and then shut off the overdrive (or drop a gear in a stick) and get to the same rpm's as before. If the stumble shows up at the lower speed but same engine speed then its probably in the engine (plugs, wires, fuel filter, etc.). If not then its probably farther down the driveline (tranny, wheels, u-joints,etc.).

bobkyle2

How old are the plugs... I would check for a misfire first... Any check engine lights