Hunting idle issue when setting timing

I've got an issue with an erratic idle when setting the timing on the Charger. When I unplug the coolant sensor, the idle starts bouncing between 700 and 1500 rpm according to the digital tach on my timing light. This of course makes it very difficult to set the timing properly.

►Initially, this started as a 'hunting' idle when the car was warm.

►We set the base idle per the instructions in the KC, and got it to idle at a very solid 900-930 rmp.

►Vacuum lines appear to be in good shape, and we couldn't find any leaks. My vacuum system is very basic and easy to inspect.

►The issue also appears briefly when coming to a stop, but smooths out after 5-10 seconds.

Have you cleaned out the idle passage and cleaned off the idle pintle/spring?

It might be easies to reset base idle again, but before you make adjustments to the throttle plate and plig your AIS motor back in, pull it off the throttle body, and spray it off really well. I suggest doing this after inducing the large vac leak, and after you unplug it as it will be at full extension. I can only assume it is "idle hunting" because the pintle isnt running smoothly, and is overshooting your idle target because of slight obstructions in the bore.

Forgot to mention that the TB is a 52mm; I disassembled and cleaned everything before installing it.

Might not cause an issue, but is your TPS in good working condition? Car might "assume" its open if it has an intermittent ground. Not running correctly in open? loop is different.

That's worth checking out. The TPS that came with the throttle body had different connections, so I just swapped one off the shelf. I'll check the voltage readings throughout the range.

Sometimes they do this, you have to hold the gas steady and let it clear out, eventually, you can let the car idle and set the timing.

Yea, i did forget that if the battery has been disconnected for a while it jas to run anywhere from 5-10 minutes to "learn" idle. Good catch!