epeterson
04-01-2015, 06:16 PM
I was driving my 1966 Cutlass yesterday when at a dead stop the carburetors backfired when going to accelerate, the backfire happened then the engine idle went up to 1000-1200 rpm' sitting and a hissing noise is coming from the engine. The idle is usually around 600-800 and now after this backfire it sounds as if air is escaping from the motor and the idle is quite high. It had a 425 big block olds with dual edelbrock 600 cfm carburetors