Idle rev

[Tal001]

Hi all

I have an issue where when the car is idle the revs go from 800 up to 2k. Today a engine light came on and a scan has shown P0171. This shows too much oxygen in the exhaust.

Any ideas?

I read it could be the DV or PCV?

Thank

[lukemk5gti]

Not the dv. A split would only cause loss of boost with throttle down.

Could quite possibly be your PCV. Rougly €100 to fix

[GrayMK5GTI]

PCV is a lot less than €100.

You can buy one for 40 British  pounds and even a child could fit one 

[Tal001]

Hi thanks for your replies

I tested the pcv by starting the car up and placing paper over the oil cap, the engine was sucking the paper in.  I Think the pcv is fine.

 Any ideas on what else it could be?

[Saintsteve]

Change the PCV.

£38 from a VW dealer.. That will be the problem.

[lukemk5gti]

Hi thanks for your replies

I tested the pcv by starting the car up and placing paper over the oil cap, the engine was sucking the paper in.  I Think the pcv is fine.

 Any ideas on what else it could be?

Would you not change hoses and gasket while your at it no? Total cost came to I think €70 and although I'd do it myself labour might bring you up anothe €30 for 30mins work