idle and starting for sure but not higher rpm's. did you remove the hose at the bottom of the reg? your symptoms are very similar to power valve issues. this hose will be connected to a plastic box (most likely under the battery). the power valve on that truck is behind the large tamper plug in the extrusion near the base of the carb, it points to the outside of the truck (away from the valve cover) the same procedure for removing the plug except this one will require larger holes and sturdier tools to pry with. what's your (e). as for custom bikes -v- forklifts....chrome exhaust trumps chrome cylinder rod every time. i'm just sayin