if i were you mate i would get the arse end up in the air and have the whole tank off, those filler pipes are a slag to change with the tank on aswell.

But i'd wip it off and check everything out.

I personally think the driving problem is also linked to this, fuel starvation.

Could be fucked cams, but if the cam was that fucked, it would be tapping like a bitch aswell.

Does yours tap?