yes,it does cancel the 1-4 shift idiocy,and lowers underhood temperature,resulting in slightly more power..it also improves the idle quality...any gm dealer should be able to order it for you...i dont know the part number,but the description should say AYBK,or something similar,and was part of a service bulletin issued from gm,for customers complaining about bad idle and lack of power when hot..im no zr-1 guru,but it did make my car happy
blackjack
sent from my black dial telephone !!