Idle hunting issue

[Durandal]

After more troubleshooting I'm still stuck at the same spot with a cold start idle around 500-750.

*Cleaned idle air control valve and even opened up the inside of the stepper motor which was clean. Checked the stepper motors bearings and that the spring was good. Did resistance checks on the IACV and they were reading 20.5 ohms.

*Checked coolant temp sensor resistance when cold and it was 2.1k ohm

*Cleaned air intake temp sensor and checked the reading on it when cold, it was 2.3k ohm

*Checked my coolant by measuring the voltage between the negative of the battery and the coolant at the rad cap. It read 0.13 vdc, 0.1-0.5 is supposed to be good.

Is there anything else I can try? I'm not completely sure it isn't the motor on the IACV but buying a new one just to test is $300+ Also really hoping it isn't the ECU on its way out.

*edit. After resetting the ECU and having to keep it from stalling by hold the accelerator in a bit, I managed to get it to idle by itself at 500 RPM. I went for a drive and then let it sit for a couple hours. Tried to start it up later and was having a hard time, it was turning over fine but wouldn't start. It eventually started and revved up to 2300 RPM and started to hunt from 1k to 2k again like it was a couple of weeks ago. I'm really thinking the IACV is bad.