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P0304 FORD Cylinder 4 Misfire Detected



Possible causes
- Faulty spark plug 4
- Clogged or faulty fuel injector 4
- Faulty ignition coil 4
- Fuel injector 4 harness is open or shorted
- Fuel injector 4 circuit poor electrical connection
- Ignition coil 4 harness is open or shorted
- Ignition coil 4 circuit poor electrical connection
- Insufficient cylinder 4 compression
- Incorrect fuel pressure
- Intake air leak
Tech notes
The P0304 code means that the cylinder 4 is misfiring or is randomly misfiring. Start by checking for intake leaks an if no leaks are found the next step is to replace the spark plugs on cylinder 4. If the problem persist more tests needs to be done to diagnose problem, see “Possible Causes”
When is the code detected?
Engine Cylinder 4 is Misfiring.
Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Lack/loss of power
- Hard start
- Engine hesitation
P0304 FORD 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.
FORD Technical Service Bulletins for P0304 code
2003 FORD FOCUS ELECTRICAL SYSTEM
2003 FORD FOCUS ENGINE AND ENGINE COOLING:ENGINE
2003 FORD MUSTANG ENGINE AND ENGINE COOLING:ENGINE
2004 FORD FOCUS ELECTRICAL SYSTEM
2004 FORD FOCUS ENGINE AND ENGINE COOLING:ENGINE
2004 FORD MUSTANG ENGINE AND ENGINE COOLING:ENGINE
2005 FORD ESCAPE ENGINE AND ENGINE COOLING:ENGINE
2005 FORD FOCUS ELECTRICAL SYSTEM
2005 FORD FOCUS ENGINE AND ENGINE COOLING:ENGINE
2006 FORD ESCAPE ENGINE AND ENGINE COOLING:ENGINE

Revisions

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