I've cleaned mine and adjusted it before, and it worked fine. You can actually remove the rheostat wire board from the assembly, and clean any residue or foreign matter off ot it. I used an eraser on a #2 pencil, which works really well, this is a trick that I learned in the militay, to clean off the gold plated contacts of PC/104 and VME architecture boards. Like mentioned above, you could also slightly bend the FLOAT arm to provide more accurate readings, but it is best to check your work with the tank down with MIN/MAX fuel. What I'm really interested in is, are there any companies out there making new SENDING UNITS with at least a larger FUEL RETURN LINE? I think that GM should have LOGICALLY used the 5/16" line on the sending unit for the FUEL RETURN, and the 1/4" line for the CHARCOAL CANISTER vent, instead.