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.
Driveability Concerns Due to Throttle Position Sensor Out of Adjustment on Toyota T100
Average mileage: 176,766 (148,596–206,000)
13 people reported this problem
1996 Toyota T100 148,596 mi, Visitor
TPS out of adjustment; how to position it again?
1998 Toyota T100 163,000 mi, Visitor
It started as a stutter at 3200-3300 rpm. Replaced plugs and ignition wires to no avail. Problem continued to get worse, replaced fuel and air filters, still problem worsened. Went from 23 MPG to 14 MPG, engine would stutter anytime you pushed the throttle past 1800 rpm and it was significantly louder and running to rich. Tonight I replaced the TPS, took it for a test drive up hills, slowed down without down shifting to "lug" the engine during acceleration, and now my T100 appears to be back to normal.