Tonight, when we got in the car the TPMS said our right rear tire was at 18 psi. That seemed odd since we had just had the oil changed and the tires checked, but we pulled over and spent 1.50 at an air pump. It put a little air in it, maybe a pound, then beeped to tell me it was full. We took off, and the TPMS didn't reset, and the readout still said 18 pounds. Stopped at another station and spent another 75 cents at an air bot only to be told it was full and it did not take any air. So the tire is not losing air, but the sensor is reporting a very low tire. It keeps going down, too; when we got home it was reporting like 14 psi. It's not any other tires either, we looked and I'm sure even w/o a mechanical gauge (which I could not find when I wanted it of course) I could tell if a tire was down to 14 psi from 35. I have searched this forum and can't find anyone with a similar problem so I'm concerned, is this such a weird problem or have you seen this and is it as simple as getting a new sensor on that wheel?