When I bought mine it was cutting out every now and again and the oil light would flash. Fixed that by replacing relay 30 on the fuseboard for about £11. Otherwise, try cleaning out the throttle body with some carb/brake cleaner and a rag, and clean out your breather hoses etc too.
I did this and then for a couple of weeks after the rev's never settled, kept going between 900 and 1400, but then settled down. I think it may have been the ecu adjusting itself.
Hope this helps