My 2001 X5 4.4 is 90K miles now. Recently, I feel the transmission (or engine?) acts strangely. When the car slowing down to <10 mph, I think the transmission is switching to gear 2 or 1, I see the engine’s rpm turning unstable. The small gas consumption meter, the one showing mpg 8~40, go up and down from 40 to 20 to 40 even I don’t paddle gas at all. If I switch to Manual mode, it works fine. No sure what problem it is. What can it be or it’s normal? ( I didn’t recognize this symptom before)