Symptoms

- Engine Light ON (or Service Engine Soon Warning Light) - Lack/loss of power - Hard start - Engine hesitation

Possible Causes

- Faulty spark plug 12 - Faulty ignition coil 12 - Ignition coil 12 harness is open or shorted - Ignition coil 12 poor electrical connection - Clogged or faulty fuel injector 12 - Injector 12 harness is open or shorted - Injector 12 poor electrical connection - Improper spark plug 12 - Insufficient cylinder 12 compression - Incorrect fuel pressure - Intake air leak

When Detected

Engine Cylinder 12 is Misfiring.

Description

When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the Crankshaft Position (CKP) sensor signal to vary, the Engine Control Module (ECM) can determine that a misfire is occurring.