Bought a 2000 reg 1.0 polo 6n2 last week and it had an empty tank so i chucked £30 in and it was almost full, i reseted the trip meter to see what mpg i would get but after 90 miles my tanks empty and keeps going up and down. not sure if this is a common problem, just wondered if somebody could give me some advice.

Also its only done 57,000 miles with full vw service history and has brand new exhaust system including cat, lambda sensor etc. and i just got my missus dad (mechanic) to service it so i dont think its major.

Really appreciate a reply. Thanks.

its probably just a dodgy fuel sender unit in the tank mate. no amount of servicing or new unrelated parts will prevent that, they just wear or get dirty and become unreliable. Its only a variable resistor and a float arm, very simple device that can easily get bad sections on its resistor track so it fluctuates. Try pulling the lead (wire) off the sender terminal on the tank and grounding the wire - the gauge should move slowly but steadily to the full mark. If so replace the sender unit.

Check the earth straps or ground lead from tank to body is not rotten either.

Edited 18 December, 201015 yr by FlySpeck

just simply leaving the car on a banked read cuased my 6n2 to gain or loose 1/4 of a tank.

its probably just a dodgy fuel sender unit in the tank mate. no amount of servicing or new unrelated parts will prevent that, they just wear or get dirty and become unreliable. Its only a variable resistor and a float arm, very simple device that can easily get bad sections on its resistor track so it fluctuates. Try pulling the lead (wire) off the sender terminal on the tank and grounding the wire - the gauge should move slowly but steadily to the full mark. If so replace the sender unit.

Check the earth straps or ground lead from tank to body is not rotten either.

Thanks very much for the help. How much would a new sender unit cost roughly and is it easy to replace ?

its probably just a dodgy fuel sender unit in the tank mate. no amount of servicing or new unrelated parts will prevent that, they just wear or get dirty and become unreliable. Its only a variable resistor and a float arm, very simple device that can easily get bad sections on its resistor track so it fluctuates. Try pulling the lead (wire) off the sender terminal on the tank and grounding the wire - the gauge should move slowly but steadily to the full mark. If so replace the sender unit.

Check the earth straps or ground lead from tank to body is not rotten either.

Thanks very much for the help. How much would a new sender unit cost roughly and is it easy to replace ?

A sender is fairly easy to replace as there is usually an access hatch in the boot floor or under the rear seat squab, they seem to be about £30 mate, heres an ebay search:

http://motors-parts.shop.ebay.co.uk/i.html...6.c0.m270.l1313