I had this issue you stated: "Some other possibly related things (that I am not even sure are problems): when the engine is revved briefly, it dips below idle, then goes above idle, then settles at idle. If the engine is revved high is does not do this."
as well as loss in power around 2800-3000 rpm, it resulted in a jerking feel. I fixed it by updating the DME software. My car used to stall all the time in traffic due to the issue above, but I haven't stalled since.