I just installed an LS1 with an 02/03 LS6 cam and advanced the timing 2 deg. The truck idles around 900 rpm's untill it warms up and then the rpm's drop steady to around 400. I was told by street and performance that I shouldn't have advanced the timing because the cam and crank sensors would be out of sync. Anyone else know anything about this, or know how to idle it up?