1995 BMW 318i low mileage

Up to about 6 months ago I used to get 32 mpg when commuting to work on the freeway everyday. One morning, I started having intermittent problems starting the car. The engine would turn over but would not start. The last time something similar happened was 6-7 years ago and the culprit was the fuel pump. When I had it towed to the dealership, they first said that they could not reproduce the problem - it started fine for them. But they kept the car overnight and poked around to see what would “break” it. After hitting the Air Flow meter they noticed that the problem occurred and concluded that this was the problem. The problem has not occurred again. However I have noticed that my mileage has dropped to 29.5 mpg on the freeway. The service manager (whose opinion I trust) says that the replacement air flow meter is a new model but there is nothing to adjust in the system. He doesn’t have an explanation for the problem. Subjectively, The car seems to idle a little rougher but maybe I am imagining this.



Any suggestions would be appreciated.

In case it was not clear, I did have the air flow meter replaced.