I have a 1996 2500 8.0L V10 that's giving me some trouble. The check engine light came on. I took it to OReilys and had them test it. Their computer said ignition coil #3 was bad. I replaced that, then the light came back on. Tested again, still reads ignition coil #3 is bad.
I was recently hauling a horse trailer with it and it was struggling going up hills. I've hauled with it before and never had it even notice a load is back there.
Could it be the ECM? Should I take it to a dealer? I miss my badass truck! 😭

 

Did you reset pcm? If not the code could still come back even after replacing parts. Was that the only code it had? You can get the codes yourself...

http://dodgeram.info/Engine-Gas/OBDI/pcm_fault_code.htm

 

Hi! We did. It took about 5 minutes for the light to come back on.

 

Which cylinders is coil 3 responsible for? Are you actually getting spark on those two cylinders? (careful, those coils pack a wallop, and can really ruin your day.)