I have a 2000 GMC Sierra with the 6.0 LQ4 and it has 320,000km on it and I get about 41psi at idle cold or warm but going down the road I’m at 60ish psi and wide open throttle it reads just under 80psi is this normal? My gauge sometimes jitters so not sure if it’s just the sensor or if I have an issue, just did an oil change with new filter hoping maybe it had been just old oil as I recently purchased this vehicle but the pressure is relatively the same as before. Any help would be greatly appreciated