Jplatt, sure not an expert but I think James has the answer to this one. Problem seem too RPM dependent where excessive return usually causes low rail at WOT. Hard to check return rate when pressure is low at cranking. Still may be a problem with both especially at that mileage. Good luckNegative, I had a truck about a year ago with the same symptoms as the op. New cp3 and a double check of the injector return rates and off they went.