Corolla & Tercel

Connect tachometer to engine. Start engine and check that engine idles properly. On Corolla models, disconnect throttle position switch terminal. See Fig 1. Gradually increase engine speed to 2300 RPM and check that engine RPM fluctuates.
Reconnect throttle position switch connector. Again gradually increase engine speed to 2300 RPM. Check that engine operation returns to normal.
On Tercel, increase engine speed to 2200 RPM and check that engine runs smooth. With engine at 3000 RPM, use a screwdriver to press in tip of throttle position switch. Engine should hesitate.
Release throttle position switch. Engine should return to 3000 RPM. With engine at idle, disconnect fuel-cut solenoid valve connector. Engine should run rough and eventually stop.
If system fails to operate as specified, individual system components. Inspect fuel cut-off solenoid and throttle position switch.

Fig 1: Testing Deceleration Fuel-Cut System (Corolla)