What causes the MAF to go bad. I just replaced mine a week ago and for the first 5 days the car was running beautifully. I purchased the MAF from my stealership. After the fifth day, the car started to run as it did before changing the MAF. I want to get a MAF put in and working, but I do not want to spend the money for a new one before figuring out why I have now had two go bad. Any ideas or thoughts on that?