my girlfriend just got a 02 v6 with 140000 miles everything is fine with the car except when your passing or under full throtle when rpms reach about 4000 the car squeals from under the hood and the rpms drop please help im only half way car savy there is a cai on the car it was installed before she bought it im thinkin it is the maf please share you opinions and tell what should be done thankyou