Hi Mick, welcome to the A2oc.
I've not done the job myself but from the attached diagrams it looks like you need to remove the undertray and work from underneath the car. Try and locate the sensor lead which runs underneath the 'banana' intake manifold from front to rear of the engine block then the sensor location should be fairly obvious.
Faulty sensors tend to play up when hot, causing the engine to cut out. When completely shot I think the engine wont start at all
Cheers Spike
