Have you tried replacing the fuel filter?
If this is the original, as most services always seem to forget its there, then it will probably be choked up.
It is located by the side of the fuel tank. It looks like a miniature exhaust silencer with a fuel pipe on either end.
Halfords jobby usually for less than a tenner!. Makes the world of difference when its done as the engine can now get plenty of fuel again.
Failing this, it may be the fuel pump itself that is not pressurising the system properly.
Steve J
August 2007