My 97 Dodge Diesel (which I drive rarely) has been difficult to start lately.  I had to use the manual primer on the lift pump to get pressure to injector pump.  I had installed a pressure guage in cab of the truck to indicate pressure feed to injector pump.  The other day I drove to a friends 20 miles away.  Truck ran  fine after manual priming again to start it.  I was parked for about 1 hour and then the truck refused to start at all.  Pumped and pumped the manual primer and the pressure gauge in cab would go up to 10 psi.   I would try to start the truck and pressure would drop to zero immediately.  I could not belive the lift pump was bad since I replaced it 3 years ago and it has only about 3000 miles on it.  It was an aftermarket DELPHI lift pump and I did determine after a lot of testing it was bad.   Apparently DELPHI brand is some real junk.  I bought a CUMMINS lift pump (they are made in China now) and installed it and the truck is running better than ever.   I found out the hard way as difficut as these lift pumps are to install it is stupid to save a few buck and buy an aftermarket lift pump.