[DonC]

If you want to check the effect that timing has on idle speed try the following.
Configure the engine to get base idle. Do this by starting with an engine that's at full operating temperature then disconnecting the SPOUT and the IAC (Also called the ISC). Mechanically adjust the throttle stop screw to just barely keeping the engine running and set the timing to whatever is recommended for the engine (usually around 10 to 12*). After setting the timing readjust the throttle stop screw if necessary. You may have to repeat the sequence of throttle stop and timing a couple of times until everything is where it's supposed to be.
Once you have the above set turn the distributor to advance the timing above your target point. Up to a certain point you'll see engine speed increase with additional timing. Retard the timing below your target and the engine speed will decrease.
Reset everything back to the base idle setting and plug the ISC/IAC back in. You should notice an increase in rpm as the ISC/IAC adds bypass air around the throttle butterflies.
Plug the SPOUT back in and you may or may not see an additional change in rpm depending on where the program has the timing set.
DonC