Is it possible for the fuel level sender to be "out of calibration?" It worked when I bought the car at 115,000km's...and for the last little while it's been reading SLOW. I have the Aeroforce scan gauge and I notice it reads too full. Fuel level % shows about 120% when the tank is filled, and it's a little all over the place when driving (like it'll read 66%-80% and fluctuate a lot on the scan gauge). Other than that it seems to read "normal" but it's too slow to move off full...it'll take 25-30 litres before the gauge moves off full, and when it's at 40 litres used, it will read about 3/4 of a tank left. Funny thing was when I put a fuel system cleaner in with the tank of gas it read accurately, maybe just coincidence though.

I say if it's totally screwed I'll just leave it, the DIC shows pretty close to the fuel used (usually off by 3-5 litres when I fill up) so I won't worry about it unless it's fixable rather than replacable.

The GM fuel level sending units are notorious for being flaky after getting mileage and/or age. The part is not exactly a marvel of engineering and very inaccurate due to the tolerances allowed on that type electrical component and using a float.

I wouldn't worry about until it goes bad to where you get really abnormal readings. Mine takes a while to come off the full mark and the sending unit was replaced about 3 years ago. However, it is accurate when the fuel level is low and gives the low fuel warning. That is the part that counts. :grinyes: