Today after driving my Metris about 30 miles I had a warning on my dash that said my right rear tire pressure sensor was missing and the little red tire symbol lit up on my dash. Those sensors are in the valve stem are they not? At any rate I checked the right rear tire pressure the old fashion way when I got home and it was 49 PSI but the tire were hot. A few hours later I checked the pressure again cold and it was 45 PSI, right where it should be. I went to pick up a pizza for dinner and on the way back the red tire symbol went out and when I go home all tire pressure sensors were working again.