From previous posts, I gather that the high fuel consumption could be because of (1) a faulty cold start valve or (2) a faulty warm-up regulator.

Question is - how do you troubleshoot / diagnoise a faulty cold start valve ? How do you diagnoise a warm up regulator.

Here are some symptoms:

1) Starts great when cold
2) Takes a few additional turns of the engine to start when warm
3) Starts with a stumble when warm and you just let go of the key after the first turn.
4) Slightly rough idle when warm. Smooth idle when cold.