Occasionally my Mk2 1.9TDi will turn over fine but not start, usually of a cold morning but can also happen when warm. A quick squirt of easy start and it fires straight away. Possibly related is a very erratic ambient temperature reading, typically 10 deg below actual. I have replaced the sensor but still erratic. I also have occasional low coolant / high temp warning light lit when all is fine. I have replaced both coolant sensors and still the same. An auto electrician had the car for a week but couldn't find any fault but thought it might be related to the ignition switch. Occasionally the fuel gauge will also stop working but often comes back next time the ignition is turned on. Are all these faults related ? Any ideas on a fix ? Obviously the intermittent starting is the only one that really bugs me. The only error code is cam position sensor but it has had this for years. 

AA out today and suggests replacing the cam sensor as he couldn't get it to start either. I will do this in the week. Anyone have other ideas ?