The car doesn't work properly in the cold, as I have noticed engine warning light flicker when changing gear between 3rd and 4th or 4th and 5th. Seems like there is a lack in power when this happens. Then the car engine completely cuts out whilst I am travelling at 40 - 50 miles hour. Had sensor fitted to engine, made no difference last year. Car is fine in summer months and then back to same problem as last year during the winter. Any ideas, as plugging it in reveals no error codes.