I ran out of gas in my wife's 1999 Toyota 4-Runner, with the gauge showing half full. I had the sensor and gauge replaced by the dealer and picked it up yesterday. (Cost $381.63) The gauge showed way above full when I left the dealer. To confirm it I pulled in to a station and pumped 16.05 gallons of gas in a tank that holds 18.5 gallons. When I started the car at the gas station the gauge then went to below empty and the low level light started flashing. In essence I left the dealer thinking it was fixed and filled with gas and am lucky I checked their work. I called the dealer and they are coming to pick it up tomorrow. The strangest thing is that after stopping and starting the engine about 6 times after I got home the gauge started indicating a near full tank which is about were it would be from the point I filled it up and got home.
I checked the local parts house this morning and they said the sensor is inside the tank and it has to be opened and drained to change out the fuel sensor. I am dissappointed there is not a fail safe test done when the mechanic completes the installation of the new sensor and gauge. It would be prudent based on the frequency of these types of problems to fill the tank completely and compare the gauge reading to the known level of fuel it will hold. It's a good thing I wasn't picking up an airplane. The mechanic had to know it was not full based on the installation method. Had I trusted the reading I would have run out of gas in about 1 hour if I was lucky. I knew it wasn't working right when I brought it to the dealer. I am not sure if it's really fixed now. I will post the outcome of the dealers findings later. Hopefully, they will at least modify the check-out procedure when they repair the fuel level indicator.