My car runs great no lose of power on the hwy but when you let off the gas at a stop sign it cuts out we have a mehcanic looking at it but he hasn't figured out the problem any ideas on what the problem is ? One guy at auto zone said it could be some thing called outer air valve or something like that any idea what he's talking about and what it looks like ? We have to take a trip to Baltimore MD tomorrow and my girl is afraid to drive her car