hobebru

I'd just thought I'd get some opinions before I start "throwing" parts at my problem with my 1996, 4.9l F150. The truck has 152k on the odometer; it is a overdrive tranny; the overdrive switch is broken, so the truck stays in overdrive. At approximately, 70-75 mph, the truck begins to stutter or miss...maybe 3 or 4 times and then smooth out after a short time, if I remain at that speed, it misses again...until I finally back off to about 65mph and it it runs smoothly then. I've put a bottle of Techron Fuel Injector cleaner into the fuel tank, at one time, and their Fuel System Cleaner per their instructions. So far, only a slight improvement. I'm ready to change plugs and probably wires next. I'll pull a plug first and go from there. Anyone else have similar problems that are reasonably close to what I've discribed above? Anything else to look closely at in the ignition system? Thanks for your help!

wde3477

Weak ignition - coil, plugs, wires, etc. Start by checking for good spark. Shop manuals (Chiltons, Haynes, Motor, etc.) will have the specs for acceptable resistance of coil and wires to save the trial and error approach.

Fuel starvation problems - filter, pump.

WAG - Don't know if Fords came with a speed limiter like some GM did - started cutting out when the limit was reached. If they did, perhaps a speed sensor problem?