I not the above, I'd guess that you it is sucking air somewhere on the low pressure side probably in a loose connection somewhere bettween the tank and the lift pump.
Also crack the bleed screw on the fuel filter and check for a good healthy flow at idle. If not then suspect the lift pump itself. Seem to have seen several of these go bad recently. Junk pattern parts.
new expansion complete. Not only are we the only Rover shop in Eliot Maine...now we're also the biggest.
"Dedicated to the resurrection of junk through engineering?"