150 hpdi surges

[bigglynn]

i have a 150 hpdi that surges real bad at high rpm primer bulb stays tight after running at low rpm about 1200 for about 45 min. I was able to bring it back up to speed again for about a min. then it started surgeing again....have any ideas thanks....glynn

[Sequoiha]

fuel filters,, more than likley the vst filter or the high pressure filter,