Bought a Certified Pre-Owned 545i two years ago and have just developed a rough idle problem at 42k miles. First visit to the dealer resulted in replacement of cylinder #1 ignition coil, however, this did not solve the issue. Returned to dealer and they assigned my problem to a chief service tech who acknowledged the problem and feels that it is most likely a worn shaft that controls the opening duration of the intake valves. Chief tech advised that this has become a problem with this model and year, and that BMW is aware of this issue. Only other prior problem was a fuel tank pressurization pump failure. Also, have sensed the car jumps a little after putting transmission in drive. Otherwise a terrific car! Any thoughts or input would be greatly appreciated!