Bought 2011 BMW X5 V8 in July, 2010. Had issues with knock sensors in first 60 days that led to reduced engine power warnings; repaired. 11 months later, +/-... start vehicle in the morning, idles very rough, reduced engine power warning, etc. Drive 1/2 mile; stop. Restart and runs fine rest of the day. Happens every few days. Same thing two days ago, runs better, but service light remains on (not reduced power, just engine light indicating need for service). Goes in the shop next Monday... anyone else experienced this with the X5 or X6 V8's? Many thanks. WBD