Bosch MAF sensors rarely (if ever) fail with lower than expected airflow figures.
The recognised within spec figures of a Bosch MAF are 480mg per stroke at idle with a fully operational EGR, and between 720mg and 740mg per stroke at 3000 RPM.
So if your Bosch MAF is out of spec, figures of 530mg per stroke or above at idle,
will not be assisted by amplification of the signal received by the ECM by the use of MAF compensation, but will be exacerbated instead.
Sure you will have a feel good factor when your over fuelling car over fuels a little bit more, but my advice would be to replace the MAF with a genuine Bosch unit if a diagnostic session dictates it's operation to be defective.
Also worthy of note here in the vein of MAF reliability, some people will advise that removal of the "bellows" section of the air intake pipe on the diesel will improve performance.
Sadly this
will result in two main things.
1 the charge of air entering the engine will be warmer and less dense.
2 it will leave the MAF at the mercy of water spray contamination, due to atomised water passing through the air cleaner, thus contaminating the platinum "hot wire" sensor reducing it's effectiveness in short order.
Brian
