I am posting for a friend of mine who has had this S80 for a number of years now. This is a quote from his last email.

"I got the car up to Chapmans yesterday where they confirmed the vacuum pump and check valve are fine. They did a smoke test looking for vacuum hose leaks and found none. The current diagnosis is a faulty booster so they ordered a replacement from Volvo Victoria (only a cool $1,000 for the part). Add another $754 for the install and (hopefully) problem solved.

When I mentioned to him it still ran like a pile of crap he was surprised - although they create 10 lbs of paper every time I take the car to them apparently they do not keep records on their customers cars. He thinks fixing the booster may solve the rough running issue - I remain unconvinced."

Chapmans is a local auto wrecker that has a number of service outlets and is generally a good source for parts, information and service. My friend is a little frustrated that the source of the rough running he is experiencing has been so difficult to find.

Any thoughts as what is causing rough running on a 2010 S80?