thegampps: No, we never did figure it out. It seems to happen only during city driving, and only at a stop light/sign. It's not every stop sign or light. Sometimes there are cars nearby, sometimes there aren't. We haven't driven a ton of miles yet, so it hasn't gone in for it's first checkup and oil change. When it does, we'll ask them to check it out. Bates: Just the sensors on the bumpers? They seem to work great other times when we're parking. I was thinking maybe we have a loose wire somewhere, but I'll check out the sensors too.