I took a performance driving course this weekend (more on it later) and found something odd. The final exercise is several runs through a mile long road course that is all curves. My 328 was suffering from very bad stumbling during this course. Here's what I know: 1. In ordinary street driving, I don't have these problems. Full throttle means full power, no stumble. I drove it 400 miles this weekend without issues. 2. What I was seeing on the track was that I'd hit the gas out of a corner, and the engine would almost die for a few tenths and then roar into full power. 3. The gear selection didn't matter 4. The gas tanks were full during these times. 5. I had no problems anywhere else during the weekend. 6. The problem happened on both left and right turns. Seems like it was worse on sharper corners, but I could have been handling the gas differently on the sweepers Thoughts? I know I lost a lot of time with the way it felt.