New at this, but I have a guestion concerning a knock coming from the cummins. No matter what the engine temp, engine speed or engine load there is a knock that is present. It is most noticeable when standing on the drivers side near the door and of course when driven down the road. I replaced the lift pump which was leaking I also took a stethiscope and listened at various places on the motor and valves on #6 hole were a little noisey so I ran the valves and #6 ext. was .025 set at 20 and that helped. After running the valves the knock was still there so I listened again with the stethiscope and #5 injector was making a racket. What is the next step and is there any chance of damaging something if I let this go for a while. The truck is a stock 96 auto with 100,000. The nearest diesel shop is about 4 hours away, so I am looking for somthing I can do myself.