The extension wire should be for the MAP sensor since its now at the front of the intake behind the throttle body on LS2 intakes.
See my truck data in the "My Garage" section here... http://www.ls1truck.com/forums/my-ga...tml#post191709
2006 silverado SS....Clifford Jr...turbo coming soon
1970 Chevelle ly6 swap....d1 coming soon