Hi , Today our check engine light came on (again) . Auto zone said code was " vacume leak" . When opening the hood , We could hear a hssssing noise (U know like air being pulled though small hole ). But after following/checking all hoses for leak we could not find ANYTHING ! Anybody had this dilemma B4 ? My neighbor ( his is auto mech.) Said to " check EGR devise ? any opinions ? Help . JIM