I just finally won a long battle with my Bonnie'* MAF sensor. What are the symptoms you're having? Any codes present? Mine was a P0102, and I troubleshot it for months, not wanting to buy a $200 sensor if I could avoid it. After cleaning it multiple times, cleaning my K&N filter, replacing the connecting wires, checking for vacuum leaks, and finding a leaky battery terminal I thought I had finally solved it. Then the CEL came on again... P0102. I finally gave in and replaced the sensor - problem solved. Gained about 5mpg city too! Just stay away from the remanufactured sensors from what I've heard. Oh, and it is located right next to your airbox on top of the throttle body, as Dan I think said.