2012 6.7 Cummina Crazy Idle

[Austin Martin]

I have a 2012 6.7 Cummins. The truck Idles crazy! When I start the truck it runs fine for about 15 seconds then starts to get choppy. I replaced the FCA with the Bosch replacement (ORiellys and dodge want 3x the amount for the new brand). I also replaced the pigtail and connector as the connector was broken. I just replaced the Camshaft position sensor. The truck is throwing a P0254 (Camshaft circuit higj) and P0088 Code (fuel rail pressure high). I have taken the truck to 3 shops and got 3 different answers. 1 said injectors "Because that's what rough idle always is". 1 shop said ECM or CP3 and 1 shop said wiring harness. None of them gave me a specific fix or garentee fix it was just opinions. Any Help on this would Be immensely appreciated!! I'm leaning on a wire or harness being the issue any troubleshooting steps or experience in this issue would be amazing

 

[Ozymandias]

Get yourself AlfaOBD and diagnos it yourself if you are be able to do that.
Stop throwing parts at it.
You want to see all return values from all the sensors to see which one is acting up.

*Truck is stock?