MAF Sensor Mystery - Seeking Recommendations

[sambowks]

Hi All

(Cape Town)

My turbo gave up and was replaced on my 2011 1.6 TDI Polo, the work was done by Steves Auto Clinic in Cape Town.
Ever since then I get a flashing glow plug light on the dash, but only when coasting in gear, or long downhills, with no accelerator. Under normal driving it doesn't come up. This does eventually trigger the check engine light.

The car drives normally and the light makes no difference to power or efficiency. The car was put on a dyno with error lights both on and off and this was verified.

The code read pointed to the MAF sensor, which was subsequently replaced with the genuine part - no difference.
It's also been checked in at Barons and they also said it was the MAF sensor - but now been its replaced to no effect.

I've read about possible scenarios where a vacuum leak of some kind among other things could cause the sensor to give strange readings and throw a code. I called a turbo place and they said there could be be an issue with the new actuator.

When I take off the oil cap there is a fair amount of air pressure which moves the cap - I'm not sure if I remember it being as much. Also read about that possibly being related to a vacuum leak.

Any takers? Does anyone know of a wizard who's good with technical details?
Please help!

[panic-mechanic]

Pm Thanas he is in the cape and could help you with the fault finding.

[sambowks]

Awesome will look him up