I was out driving around today and all of a sudden it was is as if i had restricted the gas flow to the carbs by 90%, if I floored it I would then get a good rev, but it would immediately die and stall. Pull over, always recommended when your car's not moving in a travel lane btw,wait a minute and she fires right up like nothing happened. Goes just fine and then it'll do it again. This happened twice, once before filling up from a quarter tank and once after.Oil pressure stays up when running just like normal. Gas filter is clean. Only thing different from before is a sort of mettalic hum as I accelerate, as if the exhaust bracket was loose. Haven't had time to get under and check. Also yesterday I noticed my vacuum at the manifold end was a little loose, I could increase the rpm's by manipulatuing the connection at copper tube to rubber hose. Not much, but you could tell it was different. haven't had time to pick up ne hose yet either, but it wasn't enough of a concern to cancel the drive. Any ideas?