I have a '95 F150 351 4x4. About a week ago it started to idle rough. It hasn't stalled while idling, yet. It accelerates rough and spotty, like it's hitting dead spots, and shakes pretty bad when I accelerate normally, but it shakes very little if I accelerate hard. I replaced the fuel filter, pain in the ***, and the plugs and wires are only about 4 months old. My buddy said that it might be the oxygen sensor, but I don't have a check engine light and I would assume I would get that if I had a bad sensor. The rotor and cap look fine, but I'm going to replace those today anyway, just to be on the safe side. Any other suggestions?

 

I am having a similar issue with my 93 302. I have done more work then I thought I would have to and still haven't tracked it down. Good luck.

 

Don't forget to check for vacuum leaks in lines as well as the intake manifold, etc.

Don't forget to check your fuel pressure. It could be clogged filter or pump going bad too.

Good Luck guys.......

Oh yeah, while your changing your cap/rotor, manually twist the old rotor while still attached to make sure it is free and the centrificals as well as vacuum advance can move the rotor to advance the timing. Some times these rust. It should move a little less than an 1/8 of a turn or so.