12 vavle Cummins auto
 

Okay I have a 1998 dodge 3500 auto 2wd. The rpm gauge is going crazy sometimes it will charge battery sometimes it won't and it won't shift out of 3rd gear will shift up to it but won't go any higher and will shift down. I have replaced the crankshaft position senser and checked all the wires I could find and nothing. But it's still doing it. When I turn my key to on position all the lights will come on like wait to start and all that then they will go off and a couple seconds(never turned the key to off position) later I hear like a relay click and they all come back on as if I just turned the key on. Could somebody help me please!!!!!

Could be your PCM. Unfortunately, the only way to test this is with a known-good PCM, and only one from an early '98 will work. Otherwise, I know you said you checked the wires, but that's what it was for me. Exact same problem, and I had to just take half a day to pull the entire harness apart and follow every wire fixing everything questionable I found. That was about 20K ago, and no problems since.