ISX sudden boost psi change

[Carter]

It probably is a particular mode it’s in at the time. I can get full rpm and boost if I want. Maybe I’m driving incorrectly. I just give enough throttle to get 10 lbs of boost let the rpm’s climb then grab the next gear and do it over again. In top gear I do the same and if I can hold 62mph at 10 lbs that’s the speed in run if I can only hold 54 mph at 10 lbs then that’s the speed I run. On flat ground at least.