Engine Runs
- With engine idling, disconnect injector couplers and note change in idle speed. If idle speed drop is consistent for all injectors, injectors are normal. If idle speed or quality remains the same when a particular injector is disconnected, replace that injector and re-test.
- Also, check for a clicking sound of each injector using a stethoscope during engine idle. If any injector fails to emit typical clicking sound, check wiring between ECU and injector. If necessary, replace injector.