Hi guys,
Petrol Gauge on my 2000 2.7T Audi Allroad is gone strange. When I fill up the tank it shows that it's completely empty but after about 20 miles it's showing that it's full and it stays like that for about 150 miles. After that it starts jumping up and down. I have to keep writing the mileage in order not to run out of petrol cause I can't rely on the gauge.
Any ideas?

Thanks very much, Alem