My motor is running like crap...

I'll add to the bad fuel comment...

My '65 Skylark is my "old reliable," and the other week, it would barely idle as started missing and surging going down the road. I had recently installed a Pertronix module, but it had plenty of spark. I added some of that blue enzyme cleaner to the tank, and pulled the idle needles out and blew out the idle passages with compressed air. It instantly ran 80% better. I drove it on a 200 mile round trip the next day, and now it's back to running normally. I just think I got a tank that had water/junk in it. I changed the filter but the old one wasn't even remotely plugged. Give it a shot.