I have a 96 SE that the sending unit tube developed pin hole (rust) leaks. Took it to a shop and they have tried to replace the sending unit twice. Each replacement unit (rebuilts) that they have installed seem to work out side of the tank, wired up and then simulating float movement and the guage in the dash board works. However when he installs tank back into the car the tank reads empty. According to the mechanic there is more than enough gas in the tank that it should not read empty. When he installs it he gets an empty reading and a "check guages" message on the dashboard

The car is 150 miles away with my 85 year old father & mother-in-law. I would try to do it myself but for that. in fact I put the sending unit in (junkyard find) back in February that has now developed the leaks, it worked fine and the guage worked normally. My brother-n-law took it to this shop..I've talked to the tech and he seems competent but stumped...says he has installed 50 sending units and nver had this problem..

Any help/ideas greatly appreciated.

Spit

My guess would be that the wiring leading up to the connections at the tank has an issue. Maybe when it is sitting in the "as installed" position, a break or short in a wire opens up.