X300 3.2 not starting when hot

[s2sol]

I've got a 3.2 x300 that I've owned for about 6 months. I bought it on a whim, and don't get a chance to use it much.

When I do use it, it's for long journeys. Yesterday, on a run from Cheltenham to Durham, we came across an accident on the M1. I switched the car off, thinking we'd be a while. Everybody was fine, though, so I tried, and failed, to restart the car. After 5-10 minutes with the bonnet open (in lane 3 of the M1), it started a bit reluctantly, and drove perfectly the rest of the way.

Later, it did the same outside the hospice my Father in Law is in. We've got lots of running around to do today, and I don't trust it. Is it likely to be an easy fix on a Saturday morning? I'm guessing air flow meter or a temperature sensor making it fuel incorrectly when it's hot.

[Jaguar steve]

Crank sensor - does the rev counter flicker slightly when you try to start the engine? It should, if not that'll be the prime suspect.

[s2sol]

I thought that initially, but the rev counter sits at 2-300 when it's cranking. Oddly, it's been fine all weekend on local runs in very warm weather.

We're heading home today. I'll see how it is on a long, fast journey.

[s2sol]

It did it again last night. I've also noticed the idle speed is high when it's warm. I now suspect the idle speed control valve.

[s2sol]

It did it again last night. I've also noticed the idle speed is high when it's warm. I now suspect the idle speed control valve.