I didn't have these readings until the sideways at 70 mph on the freeway last weekend. Now after car warms this pops up. If I stop at a light for at least 10 seconds it will drop to a normal reading. As I pull away from being stopped it instantly shoots up. Not a gradual move, instantly to the 1300 range. I've been monitoring it since day 1 and this is the first sign of it.
Rich