By just enabling X-Tau my car really responded nicely ( my map is well tuned ) I am just trying to understand what's going on there.
Thanks in Advance
This is here: http://www.megamanual.com/ms2/xtau.htm#tuneAs you dial-in the X-Tau parameters, the engine will likely become overly rich due to both normal and X-Tau enrichments being applied. You can try reducing the existing TPSdot or MAPdot based accel/decel enrichments, which do NOT go away when you specify the X-tau option and increasing the X-tau variables. (Note that you may have to increase the cold accel multiplier as you do this.)