A very common fault on the MK4 golf is the maf sensor can fail.
Fault symptoms include:
Rough idle
Bad MPG
Power loss
Flat spot
Engine stalls
Do a fault scan using vag com or a fault code reader to see if you get any codes.
**Note you will NOT always get a fault code with a faulty MAF!!!**
If you dont get a fault code try unplugging the MAF to see if it runs better - if it does the MAF will be faulty.
DONT BUY CHEAP!!
With MAFs i would ALWAYS say pay the few quid extra and go to the dealers.
You can get most things from GSF/eurocarparts ect but NOT MAFs or coilpacks
Lots of people have had so much trouble with cheap nasty MAFs from eurocarparts, and wasted lots of money on other things -thay assumed because the MAF was new it was fine - Not the case!!
NEVER buy cheap with these its really not worth the hassle!
Air Volume Meter (MAF) Part numbers for each engine:
06A 906 461 L - AUM, ARX, AUQ
06A 906 461 A - AQY, APK, AZH, AEG AGN
06A 906 461 G - AZJ
037 906 461 C - AGU
06A 906 461 C - AGR, AHF, ALH, ASV, ATD
074 906 461 B - ASZ .
This may be of help aswell
http://www.passatplus.de/lmm/index.htm NB - All these MAFs are now exchange items from dealers. Add X to the end of the part number above for the exchange unit part number. Price on exchange is circa £76.50 excluding a refundable deposit conditional on the old MAF being returned to the dealer.
For those who don't know, the MAF (mass air flow) sensor measures the mass of air entering the engine to control the air/fuel ratio. The sensor is incorporated into the intake system after the air filter. Bosch uses a hot-wire MAF sensor, which is a platinum wire heated to 212*F (some say 180*F) above ambient temperature. As air is sucked into the engine past the wire, it has a cooling effect that's offset by an increase in voltage to the sensor to maintain the 212*F. The engine management system then determines how long to keep the fuel injectors open. Upon shutdown, Bosch MAF sensors briefly heat the wire to 1,000*C to burn off any contaminants.
It can be found on your air box and looks like this:
To Remove your MAF :
Step 1:
Depending on your set-up, you may find it easier to take the air-box out as well.
You will have 2 philips-head screws to the rear of the air-box (Note: Thay dont come out completely).
These along with the tabs hold the cover down.
Step 2:
Gently press tab to unlock and pull plug off MAF. Tuck up and out of way.
Step 3:
There are two (each side) philips head screws that hold the MAF to the air-box. Remove these. Unlike the air-box, these come out completely.
Since they can be a bit of a pain, I recommend putting a rag under your work area. If you do drop one they will fall here rather than into the engine area.
Step 4:
Loosen clamp around neck of TIP (Turbo Inlet Pipe). Just push this down the pipe and out of the way.
You may have one of those self squeeze clamps. They are can be a bit of a nightmare. You will need a very large set of arc joint pliers.
Step 5:
Slowly pull MAF out of air-box and then out of the TIP.
You just have to wiggle it out. Be very careful not to damage anything!
The writer of this guide and GolfGTI.co.uk accept no responsibility of damage to your car when using this guide. Use at your own risk.
