Idle went nuts.

I bought a USB endoscope for $17 on ebay. Works great. I know it will fit thru a spark plug hole because I used it to go thru an O2 sensor hole (same thread) to view a catalytic converter. You can also snake it down the intake runners.

Don't remove the intake manifold before reading the detailed write-up on slantsix.org. If you don't orient the triangle and cone washers correctly, the exhaust will later crack, and don't assume the last guy knew how.