Fuel Issue

[the88bird]

I have the car running very good on the PIMPx. But it only runs good for about 80 miles after I fill up. The first 80 miles it pulls hard in all the gears but as soon as it gets around 80 miles to the tank (fuel gauge doesn’t really work right so I use the trip meter) when I get on it hard in second gear which is the gear it pulls the hardest it falls on its face around 4500-5000 rpm right where the boost starts to peak. If I drive it lightly it runs just fine for 200+ miles. My only guess is that the gas is shifting to the rear when it pulls in second gear and the fuel pump is picking up air. I should also mention that the AFR goes from about 11 to 17+ when it does this. Anyone else have this issue? Or can tell me how to fix this? The only thing I can think of is the fuel pump sits up to high for some reason or maybe I need to get a fuel cell. TIA

[Stinger]

I've seen multiple people have issues with the baffle in TC tanks coming loose which makes it where the fuel doesn't stay around the pump pickup as the fuel level goes down.

[wesk]

I second that. I tuned a very modified TC with a walbro 450 pump. Anything below 3/4 of a tank it would suck air under throttle.

[RacingJake]

I just put a 255 walbro in my 87 TC and noticed the pump sits at a 45 degree angle and the fuel sock does not seal completely at the pump either.

In your case I'd say you only used less than 4 gallons of fuel ? I'd drop the tank and pull the pump out and see if everything is OK, maybe the fuel sock is not on ? 

I'd buy a new filler neck seal before putting the tank back in too.