[BigPhattyVW]

Okay, I have replaced all rubber fuel lines, put in a hard metal line, and gotten rid of the filter before the pump. After about 10 to 15 minutes of highway driving it starts to bog and I can see bubbles in the fuel filter before the carb. This has been the most puzzling problem because I can't seem to figure out why this happens.

I have insulated the metal fuel line with exhaust wrap and aluminum ducting tape, thinking that it is getting close to the heat exchanger and may be vaporizing enough to still keep the engine going but not enough to run is steady?

I can't see anything in the fuel tank and I have removed the j tube from the tank to inspect it and it was fine. Does anybody have any clues for me?

Thanks
Clint