14 600 isx

[Boss]

filter on frame is half full air bubbles from return line in tank. engine surges or vibrates intermitantly and I hear a small popping noise in air cleaners

[Squish099]

I assume 14 is the truck year? Sounds like you are getting air in the fuel system.. Cracked pickup? Loose fitting? Loose filter? Cracked fuel line?

[hhow55]

I'm thinking it could be a bad return fuel block valve, because of the surging.