Review on Enhanced Performance Denso 197 6020 Mass Flow Sensor by Michael Jameson

If your vehicle is running lean (P2177 on 2008 Mazda 5, P0171/P0174 on most other 2-row vehicles) and your symptoms get worse while driving (compared to idling) then there is a problem. It may be due to the mass air flow sensor. Other candidates are the fuel pump, injectors, and oxygen sensors. If you're looking for an air leak, you're going in the wrong direction. Turns out that was our problem. Shortly after installing the new MAF sensor the long term fuel trim went from 20% to 5% as you can see in the picture. Denso is the recommended brand for Mazda (and I believe it's OEM). Don't skimp on it: you'll pay the difference in Tylenol tablets to find out why your new MAF didn't solve your problem.