It sounds like a vacuum leak problem. Plug off the vacuum connections temporaily like the 2 speed & vacuum wipers & then check it. Recheck the valve adjustment on #4 cyl. Pull #4 plug & see if it is carboned up.
They say money can't buy happiness. It can buy old Chevy trucks though. Same thing. 1972 Chevy c10 Cheyenne Super In the Gallery Forum