back fire

Back firing in the intake/air filter housing when the throttle is opened is a sign of a lean mixture, (lack of fuel), back firing in the exhaust usually on over run/ deceleration is a sign of excess fuel and the excess fuel is being burned/ignited in the hot exhaust system. Could be a vacuum leak, burned valve, leaking injector, or many other causes, test need to be done to determine the cause of the backfiring as it could be doing damage.

Please say u checked the anti-frezze level...