Would appreciate some advice on a problem I have with my 2005 B7 1.8T 

Car has always been well serviced and recently I have an engine idle problem - runs lumpy on tickover and when I restrict on of the vacuum lines that runs under the manifold - it clears and the engine performs fine - something in the vacuum system that is causing this - I’ve checked for leaks and can’t find any - the attached photo shows where I have a small vice grip restricting the line and the car runs 100%

any advice or recommissions would be appreciated thanks 

Paul 

I'm wondering if it's an air pressure issue with the MAF is playing up?

Thanks Steve - there are so many vacuum pipes and connectors- it’s very hard to diagnose - no engine codes at all and with that pipe slightly closed off the car runs fine 🙄

Paul