Rail pressure
 

What's the thing with the rail pressure that can pop or go bad? some cap or something like that? How do u check it?

PRV "Pressure regulating valve" Do you have a rail pressure guage? What are your symptoms? You can unplug your FCA on the back of your CP-3 while running for 3 seconds then plug back in! You should hear your enging rattle and knock real bad then recover. At this point touch your PRV carefully it should be hot to the touch. Let me know what you find!

I have quad race box. I changed to a different program. When I plugged it back in and started the truck it threw a cel. Was comething with the rail pressure. Cleared code and hasn't came back. Been driving around and turned it up and just acted funny and pressure went to 23-24,000 and kinda hung there. And before this at idle my pressure would stay around 5-6000. Not it's high 4's low 500's. I've been wanting to check it but wasn't sure what I was looking for.