Passat B6 2.0tdi 170 rough idle

[fletchie]

Hi guys,
wondering if anyone can help and offer a few ideas here!

Im pretty sure my car is not running correctly, its the 2.0 BMR 170 SEL with 135k miles. I think the car is down on power, but can't really prove that without a rolling road, but it does seem a bit lifeless below 2000 RPM. The idle is a bit lumpy at times, seems to be worse when it rains oddly enough. Once I get the RPM up past 2000 it shifts along reasonably well and is smooth.

I have changed the manifold to the metal type after the VW garage changed the cam belt and told me they could see some oil leaking from the manifold, for which they wanted to plug it in and charge me £100 probably only to later tell me they would need to investigate further and then offer a £600 + labour + VAT repair...

I unplugged the MAF today and went for a run, I didnt notice much difference in performance except the car was a bit weak getting from 70-80 in 6th. I plugged the MAF back in again, and now have an exhaust warning light on! Hopefully this will go away on its own after a few re-starts... I have read that there should be a dramatic drop in power when the MAF is unplugged? If this is the case, perhaps I will just get a new one at EuroCarParts, they're only about £60.

The injectors were changed during the recall many years ago before I got the car, and the DPF has also been changed about a year ago.

Does anyone have an idea why the car could have a lumpy idle? Unfortunately I don't have VCDS to check the fuelling and the air intake readings, and Ive had the car scanned for faults and nothing showed (before the latest exhaust warning lamp!).

Thanks in advance!