fuel temp sensor - bosch PN# "2 464 509 015-001" (note - the fuel temp sensor is the same for all 1996-2003 diesels)
injection pump top cover seal - bosch PN# "2 461 015 008-000"
First clean the area around the injection pump cover. You don't want debris entering the sensitive area of the injection pump. Make sure the engine bay is cold and have a fire extinguisher in your workspace. Make sure all combustible fumes are exhausted from the area and do not introduce any ignition sources or sparks while working on the fuel system. I also suggest wearing gloves to keep diesel fuel off your hands.
Wad some paper towels behind the injection pump. The pump is tilted forward so quite a bit of fuel will spill out. At least 5-6 paper towels are required to catch the fuel. Remove the injector fuel return line and wrap with a paper towel to catch any spilled fuel.
Remove the 3x T20 bolts and 1x triangle security bolt with the triangle socket circled below. The injection pump cover should come off easily, be prepared for some fuel to spill out. You don't want the fuel on the coolant lines or any other rubber hoses so make sure the paper towels are stuffed behind the pump!
Unscrew the fuel temp sensor (T10 x 2 screws) and replace. It's the black thermistor, the thing that looks like it's holding a pill. I don't know the exact torque for the T10 screws, but 3-4 lbs should be more than enough, the T10 screws are very small and LIGHT hand tight is more than enough force. Any more and you will strip the torx head. The heads are pretty shallow. The sensor will only fit well one way, the numbers should face up.
You can also check the resistance of the fuel temp sensor and compare it to the old sensor. It should be about 1300-1800 ohms at room temperature. With the ignition on, one side gets about 5V and goes to the ecu, the other side is ground. Also inspect for unusual wear or dirt in the injection pump area. It should be very clean with no visible wear. Inspect for bubbles or specks in the electronics and plastic - there should be none.
In my case, the bad sensor was related to an electrical short on the wiring harness. Carefully inspect the wiring harness for shorts, cracks, or rubbing. A bad sensor could also be related to water in the fuel.
If you decided to damage the triangle head bolt by hammering a 7mm socket onto it to remove it, here are some specs on the bolts