I have an 01Y V6 ES 3dr Freelander which had terrible rattles from the top end. Subsequently I have fitted a second hand Plenum from a V6 Rover. The rattles have gone but the management light has come on . My local independent has put it out with a Snap On diagnostic tool but it comes back on when it's cold. When warm the light will stay out. The tool says something like throttle flap staying open or something like that, does anyone have any ideas to put the light out for good?