I have a problem with a sympton of a miss or skip but it wont set a pattern. I have cleaned injectors, changed fuel filter,new plugs and wires, cap button new pip, newdistributor[napa] . I am looking at the black charcoal box for a possible vacumn leak, I smell gas real strong when I unplug the hose routed from the side of the throttle body. The miss will occur at idle sometimes and at different speeds but I can not make it happen by any type of driving style. Any suggestions? THANKS

 

Hows your fuel pressure? I know it's erratic, but hook up a gauge and watch it. When it skips there might be a drop in pressure or something.

 

I have a miss under load. It sounds similar to op's post.I changed the fuel filter and the problem was reduced. I feel it the most when the engine is cold. If I drive it for an hour it almost goes away except for in fourth gear. if I try to go full throttle accelleration in 4th the stumble returns.

 

Have you checked your timing? I had something similar and it was my distributor going out.

 

That's normal.Did you set the timing exactly as described on the VECI label under the hood? How wide are the plugs gapped? What did the old ones look like?



Are the wires routed exactly as shown here?

 

I set the timing exactly at 10 before tdc with the spout removed, the plugs are at 45 thousands. The old ones were squeaky white with a perfect gap. Both sets are autolite platimun. I did route the wires as the diagram explains. Thanks Steve83

 

Found my problem, I had a bad voltage regulator. Crazy thing though it would never let the battery completely discharge. I just happen to notice that after driving it at night that the start up would start to drag a little. So I checked it with a digital meter and HOT DOG it was weak on its charging .

 

If you haven't replaced it yet, I highly recommend upgrading to a 3G alternator.

 

Appreciate the idea, I think I will

 

I finally put an alternator on this truck and now I have probably put close to 1500 miles on her and she seems to run flawlessly, especially for a twenty six year old vehicle. 1985 f150 EFI 5.0 2WD. I appreciate all the help with suggestions of what to do.

 

Thanks for posting a long-term update. Most threads end as a mystery...