What could cause this

[BlueWaffle]

I have a fass 150 and just installed a RR kit last week. since i installed the RR i've noticed that after startup...the pressure will run up to 65 psi which is where I have it set. after a couple minutes of running, the pressure will rise 5psi to about 70 and hold there for a few miles. then it will just fall back down to 65 and hold there until I shut it off. it'll do it all again next time I run it. any ideas or anything i should dig more into?

 

[907DAVE]

Wouldn't worry about it, not enough of a swing to warrant any concern. Good thing is that you are actually monitoring fuel pressure.....more than I can say.

 

[AKHILF]

Anybody that does not monitor fuel pressure on there 6.0 is pretty much driving with a blind fold on. My truck acts normal even at wot but my fuel pressure drops below 40 psi but I can't tell at all without looking at the gauge. Lately it drops below 20 if I even go over half throttle so I'm parking it till a ad2 is here