Today my vRS has started fluctuating between 70 and 90 Degs on the needle also she's putting out a lot of white smoke at idle , not under load though.

My initial thought was CTS.

 

The "smoke"; does it smell of antifreeze?

Checked the coolant, level spot on. No mayo under oil cap, oil level is spot on. It's a mystery ?

CTS ?

Coolant Temperature Sensor - If it's malfunctioning you can get "all over the place" engine temperature readings.

Today my vRS has started fluctuating between 70 and 90 Degs on the needle also she's putting out a lot of white smoke at idle , not under load though.

I would say CTS is faulty and as this sends a signal to the ECU to measure fueling so could be a reason behind the smoke out of the exhaust on idle. Replace CTS and test.

Sounds like a shout. Google search reveals smoke, decreased fuel economy and fluctuating temp - all of which I have. Looks like a 5 min job as well.

Finally changed it out today. 5 minute job as advertised. Temp been solid so far. Was mega smokey at first start. But after a run there is none. Pulsating boost seems cured as well !