Ok Folks, ya ever get the feeling you're lookin' right at it but can't see it? '94 with 42k, getting the "stumbling" at 75 mph but can't see why! Runs fine until that point but cuts out everytime at 75. Carbs have been cleaned, pulled apart the gas cap and cleaned it, checked the air fliters (found a piece of papper stuck in the few weeks ago - but still have the problem). I can't see any of the vacum lines disconnected. What am I missing?