When setting cruise control at 40mph, vehicle maintains the correct speed whilst travelling on both the flat and uphill but when travelling down a steep incline, particularly one near my home the vehicle speeds up to 55mph until it levels out again and then returns back to the set 40mph.
Should cruise control have the ability to keep at the same speed no matter what the terrain or do I have a problem? I know that certain other manufacturers' cars change down through the gears to maintain the set speed. Your thoughts would be much appreciated.