Hesitation at 60 mph and up

A friend came by yesterday to have a look. We replaced the inline fuel filter near the carb, and he adjusted the carburetor and reconnected quite a few of the hoses. The car was running better then it ever had, and had a lot more power and a lot less need for depressing on the accelerator. No more hesitation at all, felt like a brand new car.

This morning I took it our for a 40 minute drive, everything went great no problems. On the way back from that drive it started to hesitate again (almost bunny hop), it didn't matter the speed, the only way to keep it steady was to depress on the accelerator more to even the engine out. I pulled over at one point and disconnected the EGR valve (as thats what solved bunny hop issues in the past). It didn't change a thing and the engine sounded terrible, it was surging something fierce, it wasn't trying to die, like it could stay barely running like that, but it was terrible. I got the car back home, and am starting from ground zero again.

This sock filter that is being mentioned, where do I find it?