My tire pressure light will come on. on 2008 Lexus RX350

In the morning, the light comes on after 5 to 10 minutes of driving and then goes off after 30 to 45 minutes of driving and then does not come on again until the next morning.

4 answers
Do you have a tire pressure guage? Check pressures in A.M. BEFORE driving it and if any tires are below the spec. on the label in the drivers door jamb (or owners manual) inflate to proper pressure next time you get to a station that has air compressor.
one tire is low check all 4 tires have the same amount of air in them
fluctuating sensor is result of drive time. air in tire heats up during drive causing internal air pressure change tripping the sensor. check tire pressure and adjust accordingly.
my tire pressure light is always on even if all tire got same pressure?