Loss of Power and Check Engine Light on Toyota Supra

The 1986-1992 Toyota Supra and Toyota Supra Turbo may lose power, fuel economy, and possibly have black smoke from the tail pipe due to a known issue with the knock sensor and/or knock sensor wiring harness.

The knock sensor is mounted to the engine, and detects knocking and pinging conditions which may harm the engine. When the knock sensor malfunctions, engine performance is decreased and fuel consumption is increased causing 'rich' running conditions. The check engine light is associated with OBD Trouble Code 52.

There are two common fixes for this issue: Inspect/repair sensor wiring harness, and test/replace knock sensor.