[DK on the road]

We were off on a 4 week excursion. I stopped at a roadside rest stop for some sleep and in the morning the engine took about 10 seconds turning over before it caught and started.

 I'd never had this happen before. I walked around back, and all seemed good except my 382 Fuel PROcessor (large plastic) inverted Fuel filter was showing a little less fuel than normal. Normally its up about 2" but now it was 1" Not too weird, but a sign I should have recognized. I traveled about 200 miles and got into a series of stop lights and at idle I noticed it was running a bit rough and down at 500 vs 600 rpm normally. I noticed hesitating or stumbling on acceleration, so I pulled into a Hobby Lobby parking lot. 

On a side note, I get a bit of anxiety towing a full-size pickup and pulling into shopping centers with random cars, islands with tree's and possibly being forced to unhook and back out. On this day the God's were with me. I just got the coach circled around and pointed towards an easy escape route when it stumbled and died.

 I was not getting fuel. Now the 382 Fuel PROcessor had about 1/4" in it.  I first thought a lift pump was failing or a pressure relief valve was hanging open and washing 60 PSI fuel back to the tank and not getting to the injectors. I was in Twin Falls ID. I contacted the local Cat dealer; they said about 4-5 days out. Cat recommended the Freightliner dealer. Freightliner said if not their chassis, they couldn't do it. The recommended a local "Big rig" RV dealer, they don't do field calls. I tried Kenworth and Peterbuilt in town and each pointed fingers at each other and said they would do me right and couldn't themselves take care of me. I drove over to the original CAT dealer that I spoke with which was only about 10 minutes away in my pickup and spoke in person with the service manager. He suggested we order a lift pump from out-of-town w $134 freight bill attached to be in hand by 9 am the next morning.

The coach died at about 11 am, by 2 pm CAT surrendered and had a field mechanic at my coach. After several hours of pressure testing and trying out used lift pumps and testing pressures, blowing through fuel lines, pulling a vacuum on fuel lines, we found 2 things.

The fitting on the top of the fuel tanks had come loose enough to allow air to enter the system. This was only visible and found when I pulled the pretty SS panel that make my fuel tank look so nice, off to trace fuel lines and verify the "fuel check valve" was working correctly.  I was losing prime, because the leak was prior to the check valve.

I was on the road and out of Hobby lobby Parking lot by 9 pm. 

Occam's Razor= the simplest solution is always the best. When you here hoofbeats, think horses not Zebras (and unicorns). 

Well in this case, it's where I should have looked first because it was simpler than I was making it out to be.

I post my lessons learned, so that other don't make the same mistakes.
Post script, we did about 2,500 more miles without a hiccup.