Hi,

Just registered as there seems to be some hugely knowledgeable forum members on here.

I've just bought a 2001 Ford Focus with 115k on the clock (I know that could be my problem)! Anyway the car runs well and I was hoping it would give me a couple of years of trouble free (or relatively inexpensive) motoring.

Over the last few days the car has developed a problem with the temperature gauge jumping straight to the red. It only stays there for a few seconds (10 maximum) and then drops back to the middle where it has stayed until now.

This only happens when driving on the dual carriageway at 60-80 mph with revs at around 4,000rpm. I stopped to check coolant levels and all seemed OK and engine didn't seem overly hot.

I know there is a sensor between the spark plugs on this model and I had the leads off recently to check the spark plug condition. The issue only seems to have developed since then.

Could I have damaged something/knocked something on the CHT sensor or associated wiring? Any help greatly appreciated!!