Hi! New to this forum. I'm trying to figure out why my '01 626 (4cyl) hesitates before accelerating. I've not had any problems with my car before. It's got about 160,000 miles on it. At one time, the dealership told me that I needed a mass air flow sensor and it was going to cost me about $400 to get it fixed. Is this right? Is this not something that could be done a littlel cheaper? Can I get the part elsewhere? Also, one of my speakers in the rear is popping. I know it's probably time for another tune up. But the mass air flow sensor has be baffled.