hey guys, I've got a 1990 sierra 2500 SLE and it is running just horridly. I'll start it and it'll run even for a bit, then just about die and rev up and run normally for a bit, then when I put it into gear and let off the clutch it jumps repeatedly like it is surging really badly. once I get it above like 35 it runs even till about 60 or so then it starts missing like crazy. little help?
