Hello to all

I am trying to fix the last few issues on my mother's GT TDI. This is 1 of 2!

It has a fuel level reporting fault, and I wanted to run this past the group to make sure I don't fit / buy the wrong parts! Ok, from full, and right down to about 1/4 full, the gauge on the dash appears to report correct information. I've run it from full to empty (with a spare tank in the boot) to see what it does.

When you watch is closely from about 1/4 downwards through use, it continues to drop as you'd expect, right down to the upper white line of the reserve tank area. I watched, and noticed that during use, it reached the upper reserve line, and then "jumped" (which is where the mis-reporting seems to start) back upto nearly the 1/4 line. From there, it started dropping back down (through usage) towards the upper reserve tank line again and whilst driving the car and the car was still showing the upper reserve tank line, the engine died and it came to a halt. At no point did it drop into the reserve tank zone, or did the yellow warning light come on.

From the point that it jumped back upto the 1/4 full line, until it actually stopped from running out of fuel, I reckon it did about 50-60 miles. So... is it the fuel sender that sits in the tank that's likely to be at fault here? If not, is there anything else it could be?

Many thanks for any suggestions or ideas!