Throttle Position (TP) Sensor: Es300
WARNING: This page is about a different car, the 2003 Lexus RX 300 and 2003 Lexus ES 300. However, it is still accessible from the selected car via links, so may be relevant.
Disconnect throttle position sensor connector. Measure resistance between terminals VC and E2. Resistance should be 1.2-3.2 k/ohms. See Fig 1. If resistance is not as specified, replace TP sensor.