I am the proud new owner of a 2007 bmw 750i. The car now has 30 miles on it. As I start the car the rpms are at about 800 and go down to 650 and go down again to 500 rpms and remain there over the course of about 3 minutes. At 800 the car is very shakey and rough, but slowly starts to steady. My former bmw 745i did not do this at all which I was very thankful for. At one time in 1986 I owned a bmw535 with the new dial a transmission sport mode and this car did the high rpms and then the slowly lowering. The oxygen sensor kept getting stuck and the car would buck like a bronco and always die on the highway plus I had at least 4 different transmissions over 2 yrs in that bmw 535. My new 750i feels just like that 535i. What did bmw do to the 750i to make it feel like that old 535i or is there a problem with my new 750i. The 745i started very smoothly in all circumstances.