This issue is getting to me. At roughly 1/2 tank of fuel the car dies. Starts back up and does it again. Gets worse and worse the more you drive it. Then put gas in it and its runs like its brand new! I have replaced the fuel filter, fuel pump with pickup sock, (no help)! The tank looks great inside. Of course only can see to the baffels. Seems like when it goes below the pump box it having the issue. Car has 256K on it. I also installed plugs, wires, cap, rotor, distribtor. I blew in the vent lines, no clogging found. Took gas cap off when I was having the problem, no help.
PLEASE help if you can... Rich

I was thinking venting, Next time it dies, try with the gas cap loose to eleminate venting as a possible problem.

I removed gas cap when I was having the problem and it didn't help. I just removed the tank a 2nd time tonight and did a detailed inspection of the fuel pump cover along with the metal tube where the pump hooks up to for cracks. NONE found! Reinstalled tank with roughly 3.5 gallons of gas in it and it still doing same problem.
I read on another Q&A page where someone replaced his tank and fixed it. That's all I have left to do. I can't see how it can be the tank. Clean inside, pump cantainer fills up when I tilt the tank back and forth. Anybody want to add something I overlooked? Thanks!

Did you check pressure as mentioned earlier?

Did you ever get an answer for this? Mine is doing the same thing. I replaced the fuel pump and at 1/2 tank it starts to stutter, and at 1/4 it dies completely. Rick