Any diesel techs out there
What codes is it throwing do you have a fuel pressure guauge on it? These trucks like to burn out fuel transfer pumps than taken out the VP44 IP if you don't catch them in time.
The first thing is park downhill and see if starts normally. I fit does, there is a air leak into the return fuel circuit. On the Dodge, three frequent issues are:
Return line fitting (banjo bolt on Dodge) at back of cylinder head loose.
The 3 way fitting that cnnnects return from head and return from IP to tank.
Inspect closely for wetness at one or more Line fittings at head. Generally this indicated a connector tube O-ring leak. New O-ring required.
If nothing found, you didn't look hard enough. The rest of fittings on IP, filter, and LP are subject to leak. You might try pressure to fuel tank filler. No more than 3.5 psi (NO, not 35) and look for wetness to show up. Air will leak quicker than fuel because much smaller molucle. I have also heard of '01 Leaking Fuel Lines (sucking air) overnight from Deterioration of the lines.
Here's a nice link to a F.A.S.S. Filtration Systems Installation How To
http://www.dieselpp.com/pdfs/mrpeal-howto.pdf