I should have emphasized upfront that most z32's do not suffer from the problems noted in this post. And I definitely did not want to imply that everyone could benefit by messing with their timing maps. However, for some unknown reason, many of our Z's have this very same low speed engine tractability issue. I know that because there are a number of members who have discussed this issue amongst ourselves, off-line. And now I think I have found the both source, and a viable solution to this problem.