I'm almost positive the 3rd cylinder on my 85 (87 engine) is the one missing. I checked all the electrical and ground connections I can think of. I pulled the spark plug and it wasn't wet or anything remarkable about it. It did seem a bit wide on the gap, but I didn't pull another to compare.

When I accelerate from a stop, the 3rd starts missing until the truck is moving a bit. It doesn't really miss at higher speeds, just low speeds under a load, like when starting motion.

I'm guessing

Timing
Wires & plugs
fuel injector on this cylinder


Anyone got any other suggestions?

 

Those would be the three main things to check. What kind of wires are you using? You need to get an ohmmeter and check resistance of the wires.