I started the game with profiler on, then I did alt+tab, turned off profiler and got back to the game and the rotation angle didn't change. But that's weird, my mate has the same wheel, we're using the same OS, in-game and profiler settings and he has absolutely no problems. I don't get it... At least it's working now.
BTW. I hope you'll do something about this huge fuel consumption. It may be quite realistic, but I don't want to drive from gas station to gas station and worry about getting there. Or at least make a few temporary refuel places like Lisa's Diner, because there's just one station on north (but it's close to the center of the island) and none on west. It's impossible to do a fast lap around Oahu.