My problem(s) appears only under 'hot' engine conditions - when standing idle it literally dies with no warning dies.....but here's the weird bit you can restart it again immediately?!!

Its a Mk3 2.0 auto, X20XEV engine and has been doing this for the last 3 - 4 weeks. Initially it was 100% and no deterioration noticed except a pretty significant heat problem, been advised to change thermostat.
Temp climbs to and remains at 100+ C or more when stuck in slow moving or stop start traffic - it will not drop in what I would cause reasonable conditions, so quite concerned Should state the fan does cut in to cool in traffic which suggest the fan switch is working fine.

Now I fear every time I hit any real congestion or traffic I am almost constantly restarting every time I sit idle for more than a minute or two.
Apart from looking a complete ****, its really really aggravating.

May be 2 separate issues or related....any ideas or suggestions.....gratefully accepted

cheers tmcd