1993 3VZE.
Did an oil and Transmission fluid change. Cleaned air filter...
Now once engine warms up and sitting at a light in gear, rpms fluctuate abnormally.

I have a new to me coil and igniter on the way as that's what Code 14 points to...
If that doesn't fix it... what are next steps with wiring?

I just find the timing odd...

Any other ideas on what might be causing this? I'm wondering now if a wire cracked in the harness or something when changing air filter...

Fluids all appear normal levels.

 

Fluids not likely the issue.
Look to the Vane airflow meter wiring going to the air cleaner.