Have a 4x2 1978 Ford F250 Custom with a 351M, a 2bbl Motorcraft 2150 carburetor, an electric Airtex fuel pump, and Holley PSI regulator. It started running ragged a little while ago, the truck fires right up and runs alright for a little while, then slows down and gets a tad rough. When I put it in gear it grabs and goes like it should but while I'm driving it, it starts running ragged and dies like it doesn't have enough fuel. When stopping in gear it dies faster. If I'm doing high speed stuff like driving up a hill it has no trouble. If I tap the gas before its about to die it picks back up, but one cant exactly tap the gas when he's trying to slow down. So I popped the carb off to clean it, and when I put it back on I had a volatile case of volcano carb. Managed to cure the volcano carb, only to discover that all my cleaning was in vain - it's still doing it.