after 15 hours driving finally got low rail pressure code. ambient 80ish degrees f, code set in the last 60ish miles of trip, 94mph 100% load 3400 rpm. after trip drove around some and sat watching rail pressure, would not increase fast if at all, did not drop at all. low side increased to 7. something bar, perhaps tired fprv, possibly small injector leak. sat for rest of day (from 1pm till 5ish oclock) log of normal highway driving with varying types of pulls, forgot to log throttle angle i think.