Circuit Description
WARNING: This page is about a different car, the 2002 Lexus LX 470. However, it is still accessible from the selected car via links, so may be relevant.
Throttle valve opening angle is detected by Throttle Position (TP) sensor and sends a signal to ECM. ECM then uses this signal to control throttle control motor which opens and closes throttle valve in response to driving conditions. Possible cause is; faulty ECM.