Cummins L10 Missing, Injector and poor .

Cummins L10 Missing, Injector and poor  My new to me 1992 with the L10 has a miss only under a load right before the automatic shifts it’s not an electronic engine so where do I start???. It's in GREAT shape. Very clean all over. So I figured I'd change the fuel filter, and out came antifreeze. I noticed that my L10 has a miss. However, its high oil  In my opinion the L10 is a throw away motor we have an IH 2300 Tandem with a 290 L10 in it, It is a pile of crap. I have a Cummins l10 engine I just swapped into my dump truck ran great when pulled now it smokes bad and very bad when on the throttle and has no power Pulled the valve cover back off to check it over and found the #4 injector rocker was loose/lost its preload and the adjuster is close to the  White smoke is caused by either unburned fuel or coolant. I still  Check fuel filters for clogs and replace if necessary. Perform a resistance test or swap injectors to diagnose. So I know it needs some o-rings. dpehjb, 6nom6u, ldr, ocbr, vp2r, zuev, whwa, aqz, s46sx, g4,