Your problem sounds very much like an issue i had with my gt soon after i bought it. When you cleaned your fuel sock how did the inside of the tank look? When it dies does it feel as though you're out of gas? (No throttle pedal) I cleaned my sock once and then had the same trouble so i emptied the fuel tank and cleaned it from above then added a new sock, returned the replacement fuel pump i had bought and haven't had any trouble since. My tank had some dirt and a fair bit of water rolling around in the bottom. I'd take another look at that new sock as that's a pretty easy thing to do on these Soobs. Gotta love those access panels, i wish all the car makers had as much foresight. Good luck, i hope I'm not sending you down the wrong path but it sure sounds the same as mine.
I guess you could ohm resistance test your current ect but I'm not sure what the parameters are for the Soob.