The 2003-2009 Lexus GX was the Americanized and Luxurious version of the Toyota Land Cruiser Prado (base model) overseas. In 2003 Lexus used a brand new cluster design which unfortunately traded longevity with lower cost.
You will notice your backlighting turning brown, yellow, or dim near the 0mph base mark of the speedometer gauge. Your needles might also twitch, flicker, and not read correctly.
Over time, the gauge cluster lens loses its anti glare coating. It becomes glossy from years of wiping and cleaning which leads to distortion and viewing problems. You will be surprised what a new lens looks like installed on your freshly repaired gauge cluster.