Serviced it and changed the belts (timing & injector pump) as well as the tensioners & pulleys within a week or two of buying it

Thought it had sorted itself out but I was mistaken, doesn't do it as much now but still does on occasion. I know it's common on escorts for the coolant temp sensor to become faulty or just plain fail and I picked up new sensor and thermostat at the weekend so will change both over the next few days

I'm thinking it's probably the sensor at fault so I'm keeping my fingers crossed