[GearHead]

black smoke is from to much fuel.
i bet your not firing on all cyl.
with the motor running, pull off plug wires from the cap one by one.
if it stalls, or runs worse, then you know that cyl is firing.
if you pull one off and there is no change, then you found one thats not firing.
use insulated or plastic pliers unless you want a nice jolt.

 

[GearHead]

those are pretty good wires. i'd run them again.
look at the auto parts store, summit or jegs, for insulated covers.
they are fiberglass, asbestos or some similar material. they are 4" to 6"
long and protect the boot and first few inches of plug wire from heat.
this will solve the problem.

 

[GearHead]

dont buy a map sensor. i'll give ya the one outta my bronco.
i dont need it seeing there is no motor in there.
this still seems sensor related.

have you checked to see that all the cylinders are firing?
pulled one plug off at a time while its running?

 

[GearHead]

what kinda shape is your wiring harness in? when i pulled my motor out, my harness went in the trash. it had several spots where there were abrasions, and most of it was dry rotted.
since this happened after you went mudding, is it possible you have some connections that got wet?
if you havent yet, take every connection and clean it out. put dielectric grease in all of them. check the plug at the puter, all the sensors, and on the drives fender when they all the harnesses come together.
i dont know if your fix will be this simple, but its easy and probably needs to be done anyway.

 

[GearHead]

this might be way off, but what are the specs on your motor? is your cam ground to work with speed density?