P0303 on FORD MUSTANG
What P0303 Means on Your FORD MUSTANG
Real FORD MUSTANG Owner Reports (Source: NHTSA Complaints Database)
"My car started to show a check engine light on around 103,000 miles. After getting a check engine light reading, the code was a misfire p0303 on cylinder 3. I took the car to a mechanic and was told the head gasket was blown and coolant was leaking into it."
"Random/multiple misfires and cyl 3 misfire (P0300 and P0303). Mechanic used a borescope and found coolant on the walls; visible coolant intrusion in cylinder 3. Coolant has gotten to low levels. Very rough cold start. Mechanic highly recommends to get the engine replaced."
"For roughly 4mths beginning in April 2025, my 2018 Ford Mustang Ecoboost has been suffering from a sporadic misfire, with it the system reporting the misfire and the check engine light coming on, the Ford App identifying the misfire occurring."
Data from NHTSA Vehicle Complaints Database. All reports are filed by vehicle owners directly with the U.S. Department of Transportation.
Common Causes of P0303 on FORD MUSTANG
Percentages based on NHTSA complaint component analysis for this vehicle.
Complaint Trend by Year
What To Do Next
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1
Check for recalls on YOUR VIN
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if your vehicle is covered.
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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.