Please help Can't figure it out
 

So I went through and put a new in tank regulator, lift pump, injection pump, 50 over injectors and tubes also the apps. Ever since I have done this my truck hasn't ran right. At an idle the voltage jumps back and forth from about 9.5 to 13.5 also the crankshaft and camshaft are married but jump back and forth from around 750 to 250. That's all that I can find wrong under idle. While driving, the first minute or two it doesn't do anything just a little sliggish. After that around 30 the rpms start jumping a little (maybe 100rpm) then around 40 the Rpms jump worse and the truck starts bucking. I have noticed it does it worse when it's hot out and not as bad at night. It does seem like the longer you drive it does start to get a little better but not by much.

Are you running an in tank pump and a lift pump? What is your fuel pressure at?

Like 15

Have you checked for codes?

Only code I have gotten recently is 1693

Also just went through and cleaned the connections for the harness and put dielectric grease on them, cleaned my battery terminals and fixed the ones that had either battery corrosion or a loose connection and replaced the trans speed sensor

If you got 1693 there are more codes somewhere. That is the companion code that always comes up. try clearing it and see what happens.

P1693 codes (SOLO) - Dodge Cummins Diesel Forum

I checked codes about a week ago and that was the only one I was getting, I'll check again tonight though

You say APPS, I imagine you mean the TPS?? If so you did calibrate that with an ohms meter and the two pins off the ecm correct? Second. Check grounds. Make sure everything is getting a good ground, go along the harness and clean all your grounds. A bad connection can make a computer do some weird things