P0304 on Jeep Wrangler
Cylinder 4 Misfire Detected
Methodology: Reviewed against the SAE J2012 generic DTC definition and NHTSA owner-complaint patterns, then scoped to Jeep Wrangler context without treating complaints as confirmed diagnoses.
Sources: SAE/OBD-II definitions, manufacturer service information, and public reliability reports (including NHTSA where applicable).
- SAE J2012 Diagnostic Trouble Code Definitions — Generic diagnostic trouble code definition reference for P0304.
- NHTSA recalls, complaints, and manufacturer communications — Used to check public owner complaint context, recall status, and safety-related manufacturer communications by VIN or vehicle.
Limits: Guidance is informational and may not match every model-year or revision. Confirm with the official manual and diagnostics before replacing parts. For safety-critical or electrical work, use a qualified technician.
What P0304 Means on Your Jeep Wrangler
P0304 is a diagnostic trouble code indicating: Cylinder 4 Misfire Detected. This code relates to the ignition system system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.
Real Jeep Wrangler Owner Reports
Source: NHTSA Complaints Database
"Brought 2013 wrangler to dealer for constant p0304 code after replacing ignition coils and spark plugs. dealer did a compression leak test to verify that the 4th cylinder head was bad and need replacing and will cost $3700.00 for the repair."
"P0302 misfire cylinder 2. p0300, p0304 & p0306 jeep/dodge is very aware of this cylinder issue and has a service bulletin for several models. (journey, wrangler, 200/avenger, challenger, charger, grand caravan, durango and grand cherokee). and they will not recall this part."
"2015 original owner, developed misfire cylinder #4 P0304, replaced coils, plugs, injectors, harness on that side. Misfire still present, noted others have reported issues with cylinder head (valves, cams, rockers)."
"I have experience a complete loss of control of the vehicle on both highways and streets that are bumpy due to dips, potholes, rough conditions due to the road."
"My 2015 Jeep Wrangler with 80,200 developed the well know Pentastar Tick. The Jeep would misfire at idle when slowing to a stop light. The check engine light came on and the code was a P0304. I'm the original owner and took it to the dealer I purchased it from."
All reports filed by vehicle owners directly with the U.S. Department of Transportation.
📊 Complaint Trend by Model Year
Common Causes on Jeep Wrangler
Based on NHTSA complaint component analysis for this vehicle.
What To Do Next
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1
Check for recalls on YOUR VIN
Go to nhtsa.gov/recalls and enter your VIN. If your vehicle is covered, repairs are free.
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2
Get a proper diagnosis
A code alone doesn't tell you the exact failed part. A diagnostic at a shop ($50–$150) pinpoints the root cause before you spend money on parts.
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3
Compare repair quotes
Get 2–3 quotes. Dealer vs. independent shop prices often differ 30–50% for the same repair.