My car makes loud hissing noise upon start up but stops like 3 ten seconds later. Also sometimes when I turn the Ignition key such that all the lights comes on then turn it anti clockwise, then clockwise, then anti clockwise and then clock wise, the check engine light blinks then stops. The hissing noise started yesterday. I think it's due for tune up. It's a 1995 dodge Avenger ES, V6 2.5L engine. How much should Tune up cost? if they are to change the air filter and clean the fuel injector? I did oil change last week and the work shop also changed the oil filter.