Engine miss, part duex

[Spitfire1975]

I have posted on this before, but not resolved it. Thought I would start a new thread in hopes of renewing interest in the problem.

I have an 86 2.9 that misses under load, almost like the engine shuts off for a split second. Always under load and always at just about 2600 RPM. Climbing a steep hill in 4th at 2600 rpm and it will do it repeatedly.

I have gone through damn near everything I can think of. Every sensor has been replaced with either a new component, or a good used one.

1. Plugs were new autolite, then replaced again with autolite platinums.
2. Wires, cap, rotor, pick up, coil.....all new.
3. All grounds seem to be in good condition and in place.
4. fuel filter and high pressure fuel pump are brand new.
5. Fuel pressure regulator is relatively new and seems to be doing it's thing.
6. All wires and connectors seem to be ok.
7. Computer is not throwing any codes.

Timing is set at 10* btdc

Overall, the truck runs really well. A short period of rpm idle hunt when first turned on (800 - 1000). Could injectors be part of the problem?

I am bringing this up again because my OTHER 86 2.9 has started doing the exact same thing and would like to figure out whats up.

Brutus? AllanD? BigJim? Enriched? Kim? Any ideas?? This issue is getting old.

 

[Big Jim M]

I'm pretty sure that engine has the ignition box which Ford used in that time period. A new one should be 25 bucks. If it hasn't been swapped in a few years there is where I'd go next.
At 2600 rpm in a level or downhill ride the engine is enjoying all the timing and lean mixture possible. Then when starting up the hill the timing gets retarded and the mixture is changed to a rich condition.
Make sure to have the plugs gapped properly. Make sure the vac advance (if any) works. I'm doubtful of injectors being the problem.
Big JIm

 

[Spitfire1975]

Thanks for the reply Big Jim. Plugs have been gapped to .044. No Vacuum Advance on this truck. By the Ignition Box, are you referring to the steering column mounted ignition starter switch?

 

[Spitfire1975]

Well, I changed the column mounted ignition switch on both trucks and, so far, it has resolved the "miss" on both trucks. Cool. Thanks Big Jim. Wish I had thought of this 8 months ago.