Need help, 95 Cummins knock
 

I am stumped i just got my buddies truck back together after i put a new timing case on (KDP) i put 4k springs, full cut DVs , and 5x.014 injectors in it and bumped the timing a tad. The first start it was fine, fired up right now no problems. Then i put the radiator back in and front end back on put antifreeze in it. Fired it up again to adjust the idle and it had a dead miss and was basically shooting raw fuel out of the exhaust. Did a power balance test on the injectors, #5 was the problem, switched #4 & #5 injectors, the miss moved to #4. Put the new injector in yesterday evening, everything was fine, took it down the road twice, no problems other than it leaked a little fuel on the return line banjo bolt on the fuel filter housing, got that fixed. He picked it up, got to town (about 8 miles away) He called me said it was popping really bad and missing. I went to look at it, it was leaking fuel at the same place. I had him fire it up and it sounded like an old "put put" JD tractor!!! :scare2: The noise it like when you tap on the push rod cover or oil pan really really hard. WHAT COULD THE PROBLEM BE??????????:s: I know it was in time when i put the cam back in. I need help really bad!! Thanks for your help.