This comes up from time to time. When they divided the gas tank in half for
the 1995 AWD models, they
added an electronic circuit that combines the output from the sensors in the
two parts and feeds the result to the gauge. That electronic circuit passes
too little current through the moving contact in the sensor to burn off any
oxides, so it eventually goes high resistance with the symptoms you see. You
can replace the sensors, they are pretty easy to get to since there is an
access panel for each tank under the carpet just behind the rear seat. But
new sensors are pretty expensive. I wrote a long article in this newsgroup a
few years ago with details on rebuilding the sensor. On my car the rebuilt
ones have been going for about 4 years I think, no problems. If I were doing
it again I would do it slightly differently. Basically what you have to do
is disassemble the swiveling assembly the float rides on, clean the moving
contact, reassemble. The problem is that the assembly is held together with
a snap-on washer that gets destroyed as you remove it, so you have to
improvise a replacement: I used a short piece of a roll pin that was a tight
fit on the shaft, cut from a longer roll pin using a Dremel cutoff disk. If
I were redoing it I think I would get some extremely flexible wire, perhaps
what we used to call litz wire in electronics but I don't know if it is
still around, and rig a lead that flexes with the motion and shorts across
the moving contact so oxidation is irrelevant. Any kind of insulation on the
wire would have to stand up to gasoline fumes. At first it seems like you
have to worry about sparks setting off gas fumes, but if that were a real
risk the tank would have blown up when the contact started oxidizing and
making poor contact. Apparently the tank is usually so overfilled with gas
vapors there is not enough oxygen to allow combustion.
Bob Wilson
