hi there had similar problem on my combo van...check the pipes coming out your sender unit on the top of fuel tank isnt rusted and holed causing air to enter your fuel system. Also check for chaffing on plastic fuel pipes. You can eliminate this by bypassing the origanal fuel system...get a gallon drum of diesel and two lengths 8mm fuel pipe, one for your main feed and one for your return. Bleed fuel system and run vehicle then let stand maybe over night and see if problem reoccurs. Cheers.
trevor
April 2008