Abe:
Try doing the basic diag thru the ignition key sequence. Turn your ignition from OFF to ON (not start), three times, and on the third time, leave it on. Your odometer or check engine light will flash a certain number of times, and that should give you some kind of fault code. I believe a 5 and another 5 is a no code thrown. There is a list of codes in the top of this forum. Otherwise, an ODB scanner would be the best bet. JiffyLube or a reputable mechanic should have one of those...
Since you didnt have a fuel gauge to see your LP failing, theres no telling how long it has been pumping too little fuel. The injection pump you have is lubed by fuel, so too little fuel== toasty pump... If you have only 80k, I`d consult the dealer about the 100k warranty. Tho I wouldnt recommend a stock LP replacement. Get the updated unit thru cummins, it pumps 17-18psi constant... the more the merrier...
good luck
-j