Hi khare, can you please tell me if the temp sensor was at fault?
I've just converted my driver from a 1.8 to a 2ltr and I am, having both of your faults. The flactuating idle (only on start up) but also the temperature gauge is reading 100, but if you spit on the block it doesn't bubble off so I presume its not actually boiling....
The book of lies says that it may be a wiring fault of some kind.