Idle speed, XJ40, Daimler 3.6, '89

Daimler, '89, 3.6, idles at 800 rpm after start from cold, when air temperature is 20 degrees plus, 500rpm when temperature is around 10 degrees, and not at all when temperature is below 5 degrees. It has to be held on throttle at 800 until engine heats.

Any thoughts?

Peter Parsons, Cornwall, UK.

Have you tested the CTS (coolant temperature sensor) for correct operation?

This is for the 4.0 engine, I assume it would be the same for the 3.6:

I would also check the Coolant Temp Sensor for proper resistance.

The idle air control valve could also be an issue for all things regarding idling.