OK, I know there are a lot of threads out there addressing this but I've got some other questions. I only drive my 2005 F250 6.0 maybe once every two weeks. I know last winter shortly after I bought the truck my fuel pressure tended to run a little higher in colder weather (after the summer passed). Today was one of the colder days now that summer has passed here in Alabama (45 degrees). I noticed I was running about 68 psi at idle vs. the usual 65 psi in warmer weather. I assumed it was due to the cooler temperatures outside and thought nothing of it. My fuel gauge read about 65 mile til empty and was on the way to the gas station. While in route, I got the low fuel warning and noticed my pressure was 70 psi while in the throttle and traveling about 55 mph. My fuel pressure has always been higher at idle so this concerned me, knowing i was under load. Once I let off the throttle the pressure started climbing slightly and got as high as 75 psi once I stopped and the truck was idling. I fueled up to about half a tank but now I'm constantly idling at 73 to 75 psi and when under load about 70 psi (55 mph without pulling anything). What could be the issue? First, is it normal for pressure to be higher at idle vs. under a load? Do yall see higher pressures in cooler weather? I do have the blue spring mod and changed my filters probably 1500 miles ago. Did I get some trash that made it all the way to the regulator from running so low of fuel? What do yall think? Am I good at these pressures running stock injectors?

 

I do see higher fuel pressure in cooler weather but to me your issue sounds like the sending unit acting up. The best thing you can do is get a manual gauge (Autozone rents them) and check to see if it matches, or gets close to, your electric.