MPG after MAF replacement

[FrayAdjacent]

Well, given the MAF is one of the primary sensors the fuel system uses to control the amount of fuel injected, AND it will go rich to protect the engine in the event of faulty signal... It's entirely feasible that you might get fuel economy increases.

[TMM986]

I replaced my MAF recently and immediately noticed better throttle response (even after I tried cleaning the old one which helped a little but not that much.)

The real return to smooth running and MPG came when I replaced all 4 of the oxygen sensors about a month later.

Now the car is running beautifully. Once you get past 40K miles it's good to replace all of the above but I would only recommend the Bosch OEM parts, not the cheap ones found on eBay. Here is a case where you get what you pay for and there are plenty of good discount sources apart from the local stealership.