There is a valve on the tranny that causes this. I wish I could remember the name of it right now but it is fairly common. If you call a dealer or tranny shop they should be able to tell you.
Black/Tan 00 SVT
Do Tinted windows count as modified?
K&N
resonatorless (is that a word)
Yokohama Avid V4S 225/50/ZR16
