I have a 2005 Fleetwood Excursion 39S with the C7 and about 74,000 miles without any engine problems. There's a lot of these engines out there and I haven't heard of any problematic fuel problems with them in the six years I've owned this MH.
Bill
Nodwell RN110 out moose hunting. 4-53 Detroit, Clark 5 spd, 40" wide tracks, 10:00x20 tires, 16,000# capacity, 22,000# weight. You know the mud is getting deep when it's coming in the doors.