I swapped my 5.3 for a cammed 6.0 a couple months back and finally it got to where It was running pretty good but starting hard. I noticed I had a cel for a cam positioning sensor so I put the cam positioning sensor from my 5.3 to see what would happen. Now the truck starts fine but says it is misfiring on all cylinders. No idea what is going on here? Anyone have any ideas?

 

Did you ever do a crank relearn after swapping the sensors???

Did you Check Fuel Pressure???

 

To better understand the Crank relearn and why it should be done after replacing sensors or PCM's read this document. CKP Variation Learn

 

Thanks for the help, The after the relearn it runs and starts much better! Finally starting to run like I want.

 

Glad to hear!