Just had an interesting development in my wife's 320i. Less than 2 weeks ago, the service indicator was showing a fair few '000 miles before a filter change was required. Since cleaning the MAF this has now plummeted to being due within 3,000 miles. Cleaning the MAF gave a definite improvement in driveability and slightly better fuel consumption.
I suppose what I'm concerned about is whether the MAF is was on it's way out or if me cleaning it has knackered it. Any thoughts ?