When I swapped in a 727 on my JTEC PCM POS controlled Magnum 360 in my Dakota R/T I had the "auto" flashed out of the PCM, since then I ditched the PCM and went with a carb, I got tired of the crap...

With the carb it runs better, faster and is deadly consistent at the track, something it never was with the PCM, even tuned by different people using a SCT.

With that said, double check all your wiring...And grounds. PCMs love grounds...not just grounds, but GOOD grounds.

 

You've got the correct flexplate/converter for the external balance, right? Not that I think that would cause your problem, but it won't help if it isn't.

If you can get it to mess up at idle, kill spark to one cylinder at a time and see if you can isolate which one(s) are missing.

You've checked compression and leakdown right?

 

I do have the correct flexplate / converter. I have not checked compression but low compression on 1 or more cylinders won't cause it to do what it's doing.

 

Low enough compression will give you a weak cylinder though, that feels an awful lot like a miss.

 

Do OHV engines hang valves? I worked on a VW that had an intermittently sticking valve, causing an intermittent misfire.

 

Anything is possible.

 

What was the verdict?

 

This thread is 4 years old. The person isn't around anymore

 

the link to the wiring diagram is bad

 

If you need wiring diagrams for 2nd gen trucks, download the service manual for your truck from here.