Engine dying?

[etg]

Hope you guys can help me diagnose this problem. I have a 350 with edelbrock carb, the 350 is a fresh rebuild and the edy is new. It was running and idling well when I first got it back from the shop. I don't have a tach so I can't give you any numbers. Then I installed a pcv valve and the idle dropped so low it would just die out. I turned the distributor counter clockwise as far as it goes, and it still dies out if I'm not babying the gas. I decided to bump up the carb and it seemed to settle down, low idle still but seemed stable. I jumped in and took some stuff to the local Goodwill to donate, and it would turn off at some stop lights. I decided to take the highway back home instead of sidestreets to keep from having to stop. Any ideas what might be happening?