Pulled the heads today. Shipping them to Hillside Cycle tomorrow. Look what I found when I pulled the aircleaner backing plate. Also did a pinion runout check. Pictured are the max readings. Is that the norm for a stock crank? Pistons had a little more carbon on them than I'd like to see. Especially the darker rear cylinder. It appears you can adjust idle on these FI motors. Isn't that what the recessed screw is for behind the TB gasket at about 5:00 when looking into the TB?
Nope, that screw is not an idle adjustment, and you really don't want to mess with it unless you fully understand the impact it can have on the operation of the IAC (Idle Air Control). The idle air control is a separate part that attaches to the throttle body, and in conjunction with the ECM it controls the actual idle speed. If you want to change idle speed, you will need to do it electronically in the ECM.
If the throttle blade setting does get moved, there are ways to reset it using a voltmeter, or a feeler gauge if close enough for government work is OK for you. It is best, however, to leave it alone.
The 2006 and earlier Twin Cam cranks had an upper wear limit of .003", and when new were around .001-.0015" in my limited experience. With the 2007 and later engines, multiply everything by four.
Jerry