I have a 2001 Dodge Ram 1500 4x4 auto with a 5.9 engine. It's been stalling just after start up. Then going down road the gas gauge will drop off all of a sudden and go to Empty. The truck stalls like a hiccup, sometimes backfires, then runs good. The gas gauge will eventually go back to where it was before. Thought it was the fuel pump because of the gauge issue, replaced it and the problem is still there. Had a shop check it out. Checked all the wires running to the tank and continuity is good. IAC motor was adjusted, throttle body cleaned, Crank sensor replaced, problem is still there. No codes ever trip. If I disconnect the battery to reset the computer it will run good then stall. The shop said the PCM is loosing power but don't know why and recommend a replacement PCM. I had one shipped from California to Idaho but when I replaced the PCM it will not start. I put in the old PCM and it will run like it did before. My question is there some security feature I have to reset that does not let the junk yard PCM work in my truck or is the junk yard PCM "JUNK"? All the truck will do with the Junk yard PCM is crank, no fire. Any serious help would be much appreciated. Next stop is the stealership. Seriously frustrated, Bill

 

Leave you original PCM in there, open up the PDC (power distribution center, right behind the battery), find the ASD relay, and swap it with the horn relay. Take the truck for a drive, and see if that doesn't improve it's attitude any.