The Throttle Position Sensor can get out of adjustment due to wear in the throttle body or due to carbon build up. This will cause the idle timing to advance more than 30 degrees which will cause very high HC and NOx emissions. Conversely, the Throttle Position Sensors can wear out and not properly advance the timing which causes a lack of power and poor fuel economy.Google+
Car Problem Reports
Toyota Previa Throttle Position Sensor Out of Adjustment Due to Wear/Carbon Build-up
Toyota Previa Problem
Average Mileage: 195,000 mi (170,000 mi - 220,000 mi)
Visitor, 1995 Toyota Previa, 220,000 mi
I changed the TPS, But need adjustment. RPM goes high whit no reason and If you shut off the engine at the beginning of high rpm, You can not start the engine for some Min.( engine gets flowed ).