Well, the main thing is that you do not want to adjust the timing with the engine running...too risky in terms of major pump or engine damage. Second you do not want to remove the two 5/8" bolts on top of the IP gear cover that hold it on. If you do it could jump timing, then you'd have to get the teeth lined back up...not good. You want to loosen the three 9/16" nuts on the pump mounting flange on the pump to gear cover studs. They are up against the back flange of the pump and they are pretty tough to get at, especially that bottom one. It gets easier if you remove the fast idle solenoid. If you want to advance the pump, you want to loosen those nuts maybe a couple turns so that you can wiggle the injection pump. It will not move much within its design limits, but remember that they are extremely sensitive. Save your current timing mark by marking where the pump flange is now in relation to the timing mark on the flange of the gear cover. To advance the timing, rotate the pump as a whole to your left, that is toward the passenger side of the vehicle as seen from the front. Retarding the timing is of course the opposite. Something a little easier is to put 12 volts DC directly to the cold timing advance solenoid on the IP once the engine has warmed up, and observe if it runs better before you mess with all that. This can be accomplished by jumping a hot wire from the positive post of either battery directly to the smaller terminal on the injector pump. Mel Agne has an Injection system service article that is in "IDI Tech Articles" that says all this and more. I suggest you read it before tearing in if you are inexperienced with diesel fuel systems. Power Service and other good fuel additives can be had at any diesel shop but probably cheaper at Wal Mart, NAPA or Advance/O'reily's Autozone etc. Timing is really tricky until you have some experience and/or the right tools so keep trying and don't give up. Be cautious and deliberate. Ask here or someone else competent if you get in a bind before you do something you're not sure of, been there done that,
JD