ManBearPig9-5

I have a 2000 9-3.....it had a front end accident(air bags did not deploy)....but when i start the car it runs like crap.....untill I take the mass air flow snorkle off a little bit(not all the way)until it runs better.......runs & drives awsome...till i shut it off....start it back up....runs like crap.......put a new mass air flow on it....still no change.....if anybody has an idea.....please help....this has me skraching my head.