This is my first posting to this board so thanks in advance for any input, and sorry to ramble on for so long. I've got an '86 745 (non turbo) with a fuel gauge problem. Searched the archives to no avail. With a full tank of gas the gauge pegs on empty, slowly working towards full, although the reading gets off the more empty the tank gets. Temp gauge works fine. Pulled the inst. cluster and checked all connections, sprayed Wurth Contact Solvent on everything. Fuel sending unit is brand new from Volvo. Parts guy assured me it was the correct unit for this car (he ran the cars VIN through Volvo NA) although he did say Volvo made a bunch of running changes on harnesses (which I had to modify), unit types and makers. When the sending unit is unplugged and the guage wire grounded to chassis, the gauge reads to full every time. I tried switching the wires at the sending unit--no dice. Triple checked all connections and ground at the tank end, even going so far as pulling the sending unit out (how many times does that make it now??)to check for broken wires or a faulty float. Plugging the old unit back in does make the gauge work better, but it will only read to 3/4 full. I ran all of this past the mechanics at the dealership (they're a couple of hours away or I'd be willing to take the car to them) and they were stumped. I am out of ideas and sure as hell don't want to spend the dosh to see if another unit would be the fix. So any suggestions/too obvious things I've over looked/black magic I should try?

TIA,

Michael Williams