Dang it Ed... you beat me to it.

98.5 is the start of the 24 valve electronic FI. The VP-44 is a well known replacement part ($1050). It can be hurt by running too low level fuel in the tank (fuel gets too hot), bad lift pump (pressure below 5 psi) too high lift pump pressure (20 psi), dirty fuel, Water in the fuel, running out of fuel (no excuse for this) and running gas instead of diesel (not paying attention at the pump...sniff the hose before fueling). If you take care of the VP-44 you will pretty well take care of any other problems too.

My 2nd lift pump is going on 125k miles and the 2nd VP is right at 100k and going strong.

The common rail motors started with the 03 model year. A completely different FI system.