the forward collision warning system on my 2018 model S seems to "work" intermittently - which is totally useless....there is no pattern at all - sometimes it works, most of the time it does not. I test it by purposely accelerating towards a car in front of me that is moving at a lower rate of speed and NOTHING - it would let me drive right into it....the lane departure warning and correction works all the time...anyone know what is going on?