I just drove my 06 S430 from GA to NYC. It drove well. Every now and then I can tell it was not shifting correctly, I would pull over, turn the car off, restart and drive and it would be fine. But now for two days it has not shift from 2nd to 3rd at all. I’m pushing almost 4K rpms and only going maybe 40mph.....any suggestions to solve this issue before I take it to the mechanic?