Outer Limits 4x4 Board

hey guys,
my mate has a 2001 gu petrol ute, and the tank keeps pressurising to the point on slopes fuel will come out.
the small hoses coming off the tank seem to be clear.can any one tell me what's wrong? It has a non vented cap, not sure if it should be vented? any ideas where to look next would be appreciated


thanks in advance steve

I am also having issues with my tank with ventialation, I am pulling my tank out in the next few weeks to try and sort it out, I will keep you posted on what I find

Sounds funny that the tank pressurizes but fuel still comes out. I have the 2002 GU and the main tank has the vent blocked with dust I think. Has vacuum problems and pressure problems which i can hear taking the cap off after a long drive & trying to transfer fuel between the tanks. Cleared the breather with some wire once and got a face full of diesel (that was smart). They have a small filter in the breather line which must get clogged, so thats the first thing i have to get to once I get back to aus. Do the petrols do the same fuel return thing as diesels?
sam