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I had a MAF replaced under warranty 3 years ago and never gave it another thought until I carried out my recent FAT tests and logged a max airflow of around 235g/s (I should be seeing 255-265g/s @ stage II).

I decided to clean the MAF myself using some Isopropyl Alcohol (from here http://www.maplin.co.uk/Module.aspx?Mod ... doy=17m10D). The result was that the MAF is now back working as it should be, and so is the preformance.

So, the morale of the story is that I would recommend that cleaning the MAF becomes part of your annual inspection, the performance tails off so slowly that you will never notice it, until you VAG-COM it that is.

The job took less than 20 mins and I've even noticed that fuel economy improve by 5% without any change to my driving style.

Nige.

For interest/comparison, my car is over 4 years old and has done 55K on the same MAF which has never been cleaned. I am still getting around 260g/s (with a new air filter - the last air filter had got dirty enough to drop that to 250g/s).

Mine is a Hitachi MAF. Maybe it has got a self-cleaning mechanism (a heater wire or similar). I must get around to checking.

General concensus is to clean it at each service.

Nige,

Could you explain quickly how you cleaned the MAF, did you just fire the Isopropyl through the duct where the wire is... or did you open it right up?

I remember an article about submerging the wire in pure alcohol.... but obviously this stuff evaporates pretty quick!

cheers

Gav

Yeah, I sprayed loads into the whole MAF assembly, put it in a plastic bag and shook it around - hardly technical, but it did the job. Be sure not to touch the wire, or inhale the alcohol just before driving

Nige.

Careful though as I tried this on my S4 once and the MAF then totally packed in

this is brlliant, just need to find a maplin store quick, my 996 maf is playing up.

All right lads take me to school - what the hell is a MAF, what does MAF stand for, what does it do and where do I find the lil blighter?

"The mass air flow sensor (or MAF sensor) measures the amount of incoming air and sends an analog signal to the engine computer representing the amount of air flowing into the engine. The MAF sensor is mounted in a cylindrical housing that is sized according to engine displacement and maximum power output."

Between the airbox and the aluminium Y-pipe you'll see one of these:

I thankyou very much Phil so take it its the mesh that needs attention de temps en temp

No Harry, its the unit plugged into the maf housing in the picture, it has a element inside this that collect sh*t an air deposits as the air rushes past ....
thats the bit to clean...

Cheers David so it's a simple process to open, clean the element then put back together or is there a knack to it?

Securi torxs screws, so you will need the special tool. Available from most tool centres on on the web. Not sure of the size though.

So do Audi techs do this as a matter of routine or would it be a customer request?

Audi techs will not do this, probably even if you ask them to.