I recently adjusted the ignition timing to 6 degrees, which I think is correct for this vehicle.
I did it at 220F operating temperature.

Otherwise the car runs fine but when I start it, the idle is at 1400rpm which is very high...
When I put it in gear (automatic transmission) the idle is suddenly normal.. and even if I put it straight back to parking gear, the idle stays normal. So the problem occurs only when I have just started the car, and the idle won't drop to normal readings even if I gave the engine some time to warm up.

Is this an ignition timing issue or something else..?