Ok have a 2000 dakota slt 3.9 42re auto 3.9 timing chain tensioner came apart end result motor is trash had a 01 5.2 not even 100k on it in my shop so motors in #7 #8 plugged and pinned tried using pcm from 01 ram crank no start it ran off little fuel in tb but died after it ran out so went back plugged in 3.9 pcm turned over fired up but only running on 6 cyl spark on all 8 no fuel 7 n 8 so I can't find a straight answer anywhere been 5 days of questions asking anyone I know what pcm do I need to make this work 5.2 with 42re trans 99 had this option 2000 had the 4.7 no one can tell me will a 99pcm work or what do I have to do to get my truck running right again

 

Does this mean you got a harness and added the wires and plugs for the injectors?
Pin outs may be different, Did you look up the wiring?

 

See if someone can flash your PCM for the 5.2....... Maybe the dealer?