I had this problem when I ran my bird out of gas (bad sending unit)I have a quadrajet 4 barrel. That being said, crap from the tank got sucked up into the carb. even with a fuel filter, very small particals can get stuck between the needle and seat. I recomend trying this before tearing into the carb. By resticting the air flow while cranking it creates more suction, and just might be enough to clear it out. I tried this, and after a few attempts, it worked like a charm