got_root?

as of today, my coolant temp display is doing strange things. It would go up to the half way
mark (where it always is once the car is fully warmed up) and then drop down to the lowest
point. I would think it's the actual sensor attached to the coolnat reservoir, but why would
the sensor read up to high and then drop down? Is there anyway (besides replacing it) to
find out if the sensor is faulty?

any other ideas?

thanks... josh