Gator ,
The only thing that I can think of looking thru my diagnostic routines is that the TFI / Pickup coil in the dist is the problem . The TFI instructs the coil to saturate and fire and since yours is firing spordically I would suspect thats the problem . Since the coil fires sometimes it makes me want to lean toward the TFI as the cause . Usually coils either work or they dont . Replacing the pickup coil in the dist along with the TFI seems to be the best practice when the TFI fails . How many miles on your truck ? Any other problems before this current one , any related problems ?
Paul