Bad demandate

[Oilysnowman]

Thanks for the help so far! I’ve got the truck more or less running smooth, but I have some more headaches. I’m not too tech savvy, but I monitored Insite the other day while I was driving, and it kept putting the truck in high altitude derate. The turbo intake air temp sensor is showing a constant 118 degrees Fahrenheit. Calculated exhaust gas temp went up to 1600 degrees, but my physical pyro didn’t go over nine…I noticed on very hot days the truck performed a lot better. Also, when I try to do the injector check valve test on Insite it says it can’t do the test due to fuel pressure sensor out of range. Any ideas?