I have had a few hiccups with the Car over the last few weeks, it started with the Idle hunting between 400 & 1800 after a run, then erratic on / off boost resulting in the car being virtually undriveable, cleaned the MAF and problem almost solved!

However..... been having a few problems with driveability in traffic, set off then hesitates, like the DV was stuck open then fine, obviously servicved the DV ( Forge 007) and it continued. Got talking to Jim At Awesome GTI and suggested that the MAF was probably degraded as I was getting an airflow, Block 003, maximum of around 134g/s and as the car had been dynoed a few weeks earlier at 199bhp should be getting approx 160g/s max flow.

So based on this sound advice I bought a new MAF and did before and after runs, before managed 137.42 g/s maximum @6240RPM and after a new MAF was fitted read 161.25g/s at 6280RPM!

Probably explains why it felt like it was lacking a bit higher in the rev range as based upon the theory that the MAF reading is directly related to BHP Produced i.e approx figure of MAF = 80% of Flywheel bhp, so a reading of 137g/s=171.25 BHP and a figure of 161.25g/s =201.56bhp

Just may help someone out there diagnose a duff MAF!!

sounds about right.......PD130 struggled to get a 118 (optimistic RR), wouldn't rev for toffee......

new MAF...HELL-OOOO.....

Check this out:put VAG COM on got 01-Engine Electronics , then to 08 - MEasured value blocks .There , inthe 10yh and 11 th blocks you can see actually how the MAF works:between 150-650 mg/s.Watch how the value increases and decreases -it must rise and drop accordingly to the engine speed. Also watch the charge pressure - from 999mbar to max 1900-2000 mbar - value seen in the same value blocks.

The given value for the MAF must rise and drop in concordance to the engine speed .

The calculation of the power output of the engine can be done like this :

1- read the actual engine torque

2 - read the engine rev speed at which the above mentioned torque is achieved

3 use this formula :

Power =0.955*Torque /Revspeed

It should be pretty accurate .

Check this out:put VAG COM on got 01-Engine Electronics ' date=' then to 08 - MEasured value blocks .There , inthe 10yh and 11 th blocks you can see actually how the MAF works:between 150-650 mg/s.Watch how the value increases and decreases -it must rise and drop accordingly to the engine speed. Also watch the charge pressure - from 999mbar to max 1900-2000 mbar - value seen in the same value blocks.

The given value for the MAF must rise and drop in concordance to the engine speed .[/quote']

Yes I agree, however if the MAF is only partially degraded you can still see the values in this block rising and falling with the engine speed but not as high values as a fully functioning MAF. In some cases the car will not show any obvious signs of problems with the MAF only it will seem a bit sluggish which the driver often puts down to 'having got used to the power' then when they get a new MAF they realise how much power this problem has been sapping.

Well then . go check another thing : the turbocharger variable geometry control capsule rod . It is attached to the vacuumatic capsule which in turn is linked to the turbocharger . Dismantle the capsule , and then check if the rod is movin freely . If the rod is stuck , then try to release it .

If the capsule's rod does not move then the turbocharger is deprived of its over boost function ,which determines the engine to advance very slowly , and the car doesn't run more than 70-80 mph.