I expect low MPG round town, but on a constant run down the M6 yesterday it never got over 20mpg but after some quick maths today of how many miles I covered and how much I'd shoved in the tank it's quite a bit out.
I had an identicle (well it was red not white) GTi about 5 years ago and that used to do 30mpg ish on the motorway. It's deffo faulty, I just wasn't sure how it worked and if this pipe could be the reason. I really must get a Haynes!
Horney