With two 535i xdrive vehicles having in excess of 130,000 miles, it is probably time to think about cleaning the intake valves. While I've seen mention of a dry ice option and one facility in California that offers the service, I haven't seen any local or DYI options. Please let me know if you have any insights.
Thanks,
Jim
2010 E60 & E61
Thanks for the replies gents. I'll probably tackle this in some form in the spring.