My midlife crisis purchase; E86 BMW Z4 Coupe

[Court_S]

Sticks. said:

I'd have thought both, and more to do with the age they are. I only mention it because it's come up a lot over the years and it's easy to check before you do anything complicated.

It seems to be quite common on the M series engines hence my question. I’ve had a look at my intake pipe but can’t see anything.

Other than the cold idle it’s running pretty well and fuel economy has gone up. It’s marginal, buts it’s higher.