Mike, I can email you some instructions but I don't see how they are correct for your setup. I verified that my 97 sender is 40-250 ohms but the instructions indicate 0-90. PM me with your email address. Vital, I already have your email so if you think the 97 instructions will help then let me know.
I went to Radio Shack and spent under $9 for a bag of test leads with alligator clips and resistor packs with 47, 100 and 220 ohm values. Close enough for testing. The fuel sender connector was disconnected and the test leads were connectred to pins B (PPL) and D (BLK) of the vehicle side of the connector. The leads were long enough to extend out from under the car so I didn't have to keep crawling under. I connected the three resistors one at a time, turned the ignition on and watched the fuel gauge. For you, the 220 resistor should make the gauge display nearly full, 100 about 1/2 tank and 47 on E. I would give you my results but that would just confuse things as I'm trying to get a 97 cluster to work in a 93. The fuel level signal on the 93 doesn't go through the PCM as it does on the 97 and I'm assuming on the 99. If the gauge displays correctly with the three different resistor values then the sender is at fault.
One thing I did learn today is that the rheostat on the 97 sending unit was easily removable from the sender assembly. I wonder if just the rheostat can be replaced rather the entire sending unit assembly. The sender I bought for the 90 was $118 but a rheostat might only be a few bucks. Something to look into.