My V70 awd (140K--just had new timing belt put on) seems to have what I can describe as a hiccup if I jump on the accelerator at, say, a passing speed (Between about 50 and 70 mph). I am planning a long-distance trip this weekend, and the car runs fine except for the hiccup, but I wonder what might be causing it. Check engine light does not come on, and as I mentioned the car is running very well otherwise, but I'll be traveling at freeway speeds and might need the oomph of the passing kick.