At least refine how well it's working.. I was driving an M3 up a hill and it would go to 20mph and upshift... then slow to 8mph and downshift... then speed back up to 20mph and upshift.. and back and forth again... very annoying.
I was finally able to stabilize it at about 16mph by playing with the W key, but the game should be smart enough to recognize not to upshift if the next gear up can't handle the incline.