scspeedster

I have a 67 Mustang 390 with a Holly dual-line. On my fuel line I have a "see-thru" filter that never fills up. Gas surges in and empties, but never very much. The car runs good, except at extended runs, like on an expressway at 65, it coughs and sputters sometimes like is out of fuel.

I just replaced the fuel pump, thinking that was it. Any suggestions would be appreciated.

Soaring

My see through filter stays about 1/2 full all the time. You may have some blockage either in the line or in the tank. Sounds like you aren't getting enough fuel to the carb somehow.
On Edit: I just thought of another possible cause. When I used to store mine in the winter, the tank collected condensation, and the water in the fuel caused mine to cough at highway speeds, but not idling. Have you ever drained your tank?

scspeedster

I haven't seen any evidence of water anywhere, but, no I haven't drained the tank. The fuel filter used to stay full all of the time, I wonder if it could be a carb float adjustment?

dozierstang

Hey, got a 67 390 GTA myself. See through fuel filter stays full on mine. Check fuel lines and sending unit. Also check filter on carb if you have one of them too. I put a Holley 4160 on mine and it has a strainer on the carb that could possibly be clogged.

Colorado_Mustang

My see through filter doesn't fill up, and I have a 165GPH electric pump.

Double check your floats and you may want to check the filter in the tank as well.

Soaring

Yeah, my see through only fills about 1/2 full. If it were mine, I would drain the tank, pullout the sending unit and check the condition of the filter on the end of the pickup tube. Also, use a flashlight and look around inside the tank for rust. If no rust, then I would put about 5 gallons of fresh fuel in and see if that solves the problem. If it doesn't, then I would blow out the lines. If that didn't solve the problem I would replace the fuel pump.