i have a 6.2l gm diesel ive replaced both the return and feed lines new holly 32gph lift pump new filter but after driving for 30 mins or so 1 start getting air in the lines I let it sit for 5 to 10 min and I'm running again any ideas would help I'm new to working on diesels thanks

 

You need to check all new connections that you recently made for tightness. any hose clamps may not be tight enough and sucking air especially on tank side of new pump.If filter is screw on check for tightness and missing gasket. Good Luck!