[68gmsee]

Re. weak pump. I had a similar issue with my 69 truck. It would run okay for a while and then die out. Pump did the same thing yours is doing. Pump a little gas into a jar and then it trickled down. I replaced the pump and found the old one had a small crack in the diaphragm.

Few years later I had a similar symptom on my 68 and figured I would be smart and replace the pump right off. Wrong! Turned out to be a restricted fuel line from the tank to the fuel pump. Made a new one and that solved that problem.

Other fuel problems I've had were restricted fuel filter sock inside the fuel tank and unvented cap in fuel tank.

Below is a pic of a vented cap so you can tell the difference. You can gently insert a thin object and push on the inside piece. It's spring loaded and should move up and down slightly.