Originally Posted by fishwater
TPMS sensors by design are extremely accurate while manual tire pressure gauges even expensive ones are generally off. Since you checked it with two separate gauges hopefully of good quality I would say the vehicle is doing something on the display. I sell TPMS tools & sensors, I have checked my sensors hundreds of times during demos & mine are accurate to the Evic within .3 lb. I would recheck the pressure with a high quality gauge & see if the readings are different. The other option if your really curious is to check the sensors with a quality TPMS tool like the Bartec, by reading the sensor at the wheel you will have the exact pressure reading of the sensors before the info is sent to the module. Most every major tire chain has a Bartec 400 & it takes less than 5 minutes to check.
I am about to put a set of after market 22's on my truck and I need some TPMS sensors. What am I looking for as in price and where to buy? Do they just set in the wheels?