Electric Fuel Pump Issue

[Brownwood]

We have had some great weather here in Texas so I have been driving the MGB V8 every day at lunch.  I am having a strange fuel pump issue.  I have a red Holley street electric fuel pump mounted back near my gas tank with 3/8 lines throughout.  It works great when I first start driving but after the car warms up and I drive for 10 minutes or so, the pump output slows to a trickle.  The car still runs but it has no high speed performance because of fuel starvation.  The next day, same thing all over again, lots of fuel at first then slows to a trickle.

I haven't torn into the fuel system yet but this just seems odd and I wondered if anyone has had a similar problem?

[HealeyRick]

Try it without the fuel cap on first, maybe something as simple a a clogged cap vent.

[joe_padavano]

Either it's a plugged vent as suggested above or the inlet sock in the tank is collecting crud as fuel flows through it, clogging it.  Once you shut the pump off, the crud drops to the bottom of the tank and the cycle starts again.

[Brownwood]

Thanks Guys.  Ill start with the plugged vent idea and work from there.  I did pull the gas tank filler cap and there was a big woosh of suction being released, so I thought it must be the plugged vent but even with the gas cap removed the pump continued to not pump much fuel.

[Justinb]

My vote is for the plugged pickup in the tank. I had the same problem but with an efi system and it ended up being the pickup.