thx for replies . To answer a few questions. Car ran great for 20 years. No changes to set up. One hot day last summer cruising highway speed it just died. Towed it home and it restarted. Has never been reliable since. I have tried 3 different coils. ( btw Greg) its now got the tko 600 in it i got from you in columbus. Im pretty sure i tried it in cooler weather and had similar results. it is warm here now. Will try it on cooler day . Pulled gas line at fuel pump and gas runs freely from tank. Balance of fuel lines are new. Will pull and check again. I put fuel pres gauge on line to carb always reads about 8 pounds . Planning to plumb it where its visible when driving to see if there is a pres drop when it dies.  thx

The air filter hasn’t been on in months as I’ve been chasing the problem.  When I move throttle it pumps gas ,  just seems to run out of gas When accelerating , One thing I noticed is wet black moisture out tail pipes when idling.

Have a stock 69 mustang 428 cj 4 spd.  Runs fine cold. After about 10 minutes of operating temp engine dies out under load . Will stop running. After a minute or 2 will usually start and limp home. So far i have changed fuel pump. Carb 735 holley. Distributor, fuel filters. ,pulled sump from tank replaced screen. Blew gas line out , changed coil ,  kind of at loss now. Anyone have suggestions? Thx