Idle control without TPS?

I'm having difficulty with idle at various temperatures. I'm not using any air valves or drive-by-wire – basically old-school throttle cable and an idle set screw on the plenum. If I enable idle ignition control, everything works pretty well, except I can't "exit" idle control, as it seems to be looking for throttle position % (which I'm not using). Is there a way to use idle ignition control without referencing throttle position? For example, it appears to use RPM to enter idle control. Can I use RPM and/or vacuum to exit idle control?

Thanks in advance.

You really need a throttle sensor to know if the engine should be idling. For example, if you were in too tall of a gear, and lugged the engine, but had 80% throttle, you wouldn't want the idle control to kick in.

I would fit a throttle position sensor, or at least a switch that could be configured to indicate idle was desired.

Throttle Position is a Critical Sensor in the M1 architecture, it is not a channel that can be ignored.

Okay, thanks guys. Up to this point, the lack of TPS hasn't been an issue, and I've found that I can tweak timing based on coolant temps and engine load to get a decent idle. The idle ignition control works better though, so it seems a TPS is in my future.