IF you have a problem with your fuel gauge, not showing full tank of gas this might work for you, well Since I bought the car, there was a problem with fuel gauge. Full tank of gas was showing 3/4 of fuel, no matter how many times I filled all the way up. What I did few weeks ago (since i was testing it and wanted to make sure it worked) I filled all the way to the top, and gave one more tap, (be care full some fuel may spill, but not much, there's a drain anways- THAT FIXED the problem my fuel gauge is back to normal. it shows full tank of gas and i filled the car all the way to the top few times all ready.

 

Do you fill it in this way every time now or was it a one-time thing?

 

I've had two instances where I've put in some gas (like $20) while on empty and the gauge didn't move at all. First time it happened I thought station took my money and didn't give me any gas.
Recently the tank would not take any gas, this was after having the car sitting almost a month, I could hear air hissing from the tank but no matter what I did gas would not go down. Waited till next day and then no problem at all.
I think there are known issues with the tank and fuel gauge....

 

Just one time

 

Yep I think it happens when the car sits for several months. It gets sticky or something I know my car was. For months and months. I awlays fill all the way. Some people say you have to empty the tank to fix the problem with sticky gauge

Also when you dc battery and you low on fuel gauge may drop so yo have to fill it up at least. 3/4 of a tank so it relearn. Weird

 

Realize there are two sections to the tank. The sensor is in the top section. So unless you can fill into the upper section the sensor doesn't know it. It estimates how much fuel is left based on the OBC mpg estimate at the time the sensor reads no gas in the top hump...

And from the workshop manual:

If the power supply is interrupted by a discharged or
disconnected battery with the tank containing less than
19 l, the calculated value for the range on remaining
fuel in the instrument cluster will be incorrect or
deleted.
·
If the tank contains less than 10 l, it is possible that the
fuel level warning light is no longer activated.
·
If the power supply is restored with the fuel level at
less than 19 l, it is possible that the fuel level display
may subsequently display too much.
·
This may lead to the vehicle breaking down.

Remedy:
 Refill at least 19 l of fuel; then the
fuel level sensor is in operating
range and its display precision is
guaranteed.

 

I found filling the tank up completely and then removing the black cable to the battery has reset my gauge.

 

Had same problem with gauge not registering correctly when I ran it really low. Though it eventually self-corrected, I found not running it to fumes avoids the issue altogether.