Hi everyone, I have a 2002 5.9 L V8 second GEN that has just under 100,000 miles. Recently I was having some motor issues and it was just easier for me to replace the motor. Went and bought the exact same motor that was in it before (except this motor is of course brand new) and had it replaced. Got it back and it had a large exhaust leak at the manifold. Sent it back, got the exhaust fixed but once I got it back, it did not want to celebrate quickly once over 1700 RPMs, it was idling weird, and the check engine light came on but I could not pull any codes. I then played with it for a day or two while the check engine light turned on and off every other time I started the truck. I was finally able to pull a code which was the crankshaft position sensor code. which did not lead me anywhere. I then went back to it the next day and the code did not show. I decided to ask around and call the mechanic who replaced my motor and he mentioned the PCM quite a bit during our conversation. it quickly became the topic of our conversation with him telling me that the PCM was most likely my problem being that they would often go on the older Dodge’s. I Finally went and got a proper code pull today with equipment 10 times better than mine and I had 7 different codes come up.

-crank shaft position sensor
- ignition pick up coil
-camshaft position sensor
-ignition distributor
-powertrain control modular(PCM)
-vacuum hose
- p1391(Intermittent loss of CMP or CKP)

for some reason, my mind and close friends who have been around cars and works on them their entire life are telling me that all of these are showing up because, 1.I got a new motor installed, and my PCM is simply not happy or it has completely taken a crap. I’m lost, I’m annoyed because this truck has been giving me nothing but hell recently, but it is my only vehicle and I need to figure this out.

please share your ideas I am all ears, thank you very much​​​​​​​

 

Based on what you're saying, I'd replace the crank positioning sensor. It's very common that they get damaged when swapping engines since they bolt to the engine and reside between the engine and transmission. The P1391 code leads me to the crank sensor, since the engine does run, but not well. If you decide to replace it, please install a MOPAR crank sensor, as these engine are very finicky when using an aftermarket crank sensor.