Hello,
Was the cp4 to DCR conversion due to a failed cp4 or completed before a failure? Was it completed before the delete or at the same time?

And to confirm you have already replaced the FPS on the fuel rail? Was the driver side fuel rail also replaced?

Also, what's the tuner and is it in a stock, tow or 'race' type setting (since you stated this all began after the delete and tune install).

 

So the cp4 to dcr conversion was done because the cp4 pump failed but the pump failed months after the truck was deleted and tuned which that’s when the low fuel pressure warning began .also I believe the custom tune on the truck is a race tune I don’t have a tuner to change any settings and out of all the parts that I replaced I haven’t changed the driver side fuel rail

I also forgot to mention this warning only comes up few seconds after start up then I’ll press the reset button on the steering wheel and it will go away it will only come back if I turn the truck off and back on

 

When the cp4 failed was there metal contamination in the fuel system?

Do you know what your desired and actual fuel rail pressures are and have you checked the FPS KOEO (ref P01C6)?

There have been instances of both regulator and sensor on fuel rail being changed out with zero improvement. There is an orifice in the driver side rail which in some instances cause problems, but not certain it is your problem without more testing. It could be a bad injector, ... have you run any tests on injectors / cylinder contribution balance?

 

When the cp4 pump failed in my case I was lucky enough not to find any metal contamination anywhere it just failed and my truck left me on the side of the road.

now as far as the fuel pressure sensor on the fuel rail I haven’t changed that sensor yet. I did change the fuel pressure regulator on the other side of the fuel rail and the fuel pressure switch sensor on the fuel line next to the temp sensor.

Also I haven’t checked the fuel pressure readings

 

2 codes with no cel..

truck is tuned and deleted with 260k miles

I also forgot to mention this warning only comes up few seconds after start up then I’ll press the reset button on the steering wheel and it will go away it will only come back if I turn the truck off and back on

This could be a tuning issue.

 

Here are my readings at idle after stopping off the freeway at night probably 75F. Look specifically at fuel pressures.