chariotdriver

It could also be the fuel heater. They get hot, melt, leak air letting the inlet fuel to the LP go back to the tank. Get rid of it; really doesn't do any good on a 12V engine as it is a foot away from the fuel filter which is the problem with fuel waxing.
Also check the fuel return line between the p7100 and the block. Prone to cracking/leaking causing start issues in addition to fuel leaks.

yesav

There is no external leak. No drips on the garage floor or driveway. The undercarriage and engine are exceptionally clean except for some oil spots caused by oil and filter changes that have collected dirt.

oliver foster

Since the LP is SUCKING fuel from the fuel tank those lines would be under vacuum when running and never show up a wet spot / leak.

I am telling you, that you have a leak in the fuel system, somewhere from the fuel tank to the motor that is letting air into the line when the truck is not running. I have no doubt in my mind, if those are your symptoms, that is your problem.

I have been there and done that several times before with several different 12V Dodge trucks.

Do what you would like with that info..

chariotdriver

Oliver is right. My problems happened with the fuel heater which is on the suction side of the LP; no leaks of fuel but lots of leaks of air into the fuel system.