I have the 2.5L 6 cylinder engine and when shifting gears and accelerating the engine sputteres/misses/hesitates, then clears itself out. Twice it has turned on the check engine light. Other than that it has been a great car. It has 92,000 miles.
engine sputters/misses when accelerating on 1999 BMW Z3
The Check Engine Light having illuminated means there is a code stored in the computer of your car that will indicate what the computer in your car saw the moment it experienced the misfire or drivability problem. A scan tool is needed to to retrieve the codes from your computer through a 16 pin diagnostic socket under the dash of your car. Any repair shop should have a diagnostic scan tool, a BMW specialty shop or dealer may have a more advanced scan tool but your problem may be a failing ignition coil.