sounds like there may be something in tank that is intermittently blocking off outlet pipe, when high speed the fuel will enter pipe a lot quicker and take foreign matter with it,but when at slow speed it wont show the same.[had this once on a pilot and it turned out to be a piece of crisp bag-which i thought would have floated on top but it sank to bottom.] still dont know what ldv you have! but you may have to take tank off and clean it out.
k
November 2011
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