Fiat doblo cargo. Fuel problem

[Knot]

I've got a problem with my fiat doblo cargo. It's runs really well but only when it's got more than a quater of tank of diesel. Any thing below that it keeps stopping and won't drive very far. Also the gauge keeps going up and down. Thanks in advance

 

[Burnerman]

On rare occasions the dip pipe (that draws fuel from the bottom of the tank) can come adrift or rust through......I guess thats the problem with yours.
The gauge and fuel pump comes out as one unit.
John