Mitsubishi i car - limp home mode - Chris Atki

Long shot, with only 600 sold, but after 3.5 years and 30k miles no probs, the car now goes into limp home. Garage is stumped (never seen one before- the garage that sold the car has closed). it is a KEI car, 600 triple with turbo.

17 mph on motorway a little exciting!

Has anyone experienced this or got any ideas of what would fix it - thanks.