http://forums.hybridz.org/index.php/topic/100157-hei-tac-issues/page__p__939215__hl__tach__fromsearch__1#entry939215
http://forums.hybridz.org/index.php/topic/100044-gm-hei-question/page__p__938197__hl__tach__fromsearch__1#entry938197
If you search you'll find more info, using the correct spelling will help as well. Remeber its Tach not Tack.