Deceleration/Idle Switch
- Unplug deceleration/idle switch connectors on throttle body. Connect ohmmeter to switch contacts. Switch should show continuity with throttle valve closed and with throttle valve fully open.
- Run engine at idle speed for a short time. Stop engine and turn ignition on. Unplug connectors from deceleration/idle and full throttle enrichment switches. Voltage between connectors of throttle valve idle switch should be 1/2 volt. If not, check for defective control unit or wiring.
- To check deceleration function of switch, test results of step 1) and 2) must be positive. Plug in all throttle valve switch connectors. Temperature at coolant sensor must be at 140°F (60°C) or more and resistance below 550 ohms.
- Accelerate engine slowly. At the same time, operate deceleration/idle switch by hand. Engine speed must fluctuate. If not, replace control unit.