Intermittent Stalling...

My motor has stalled on me several times of late, while approaching a junction. It happens when warm or cold and is very intermittent, think it's happened 4 times in the last 2 months. Now it's just been serviced and the temp gauge sits in the centre and it warms up in what I can only describe as the normal time (i.e. the time it's always taken). Also just 2 years ago the temp sensor in the engine was changed, but at the time all sorts of wierd things were happening. Was wondering if this fault could be due to the sensor in the exhaust incorrectly reporting the temp to the ecu.

Any thoughts please guys.