P0304 on FORD MUSTANG — Cylinder 4 Misfire Detected

Q: "What does P0304 mean on a FORD MUSTANG?"

"P0304 indicates: Cylinder 4 Misfire Detected. This is a ignition system code. 2 FORD MUSTANG owners have reported this to NHTSA."

Q: "What are the most common causes of P0304 on FORD MUSTANG?"

"Based on 2 NHTSA reports, the most commonly cited components are: Engine. These percentages are based on the component field in owner complaints."

Q: "Is P0304 serious on my FORD MUSTANG?"

"Of 2 NHTSA reports for this code on FORD MUSTANG, none involved a crash or fire. However, any diagnostic code should be evaluated by a qualified mechanic."

Q: "What should I do if my FORD MUSTANG shows P0304?"

"1) Check for recalls on your VIN at nhtsa.gov/recalls. 2) Get a professional diagnosis — a code alone doesn't identify the exact failed part. 3) Get 2-3 repair estimates to compare."

What P0304 Means on Your FORD MUSTANG

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.

2 FORD MUSTANG owners have reported this issue to NHTSA across model years 2019. Most reports come from the 2019 model year. The most commonly reported component is Engine (100.0% of reports).

Real FORD MUSTANG Owner Reports

Source: NHTSA Complaints Database

"Have a 2019 Ford Mustang 2DR 2.3L Ecoboost with 59,500 miles which I took to the dealership with a code P0302 and P0304 present, cylinder misfire, observed coolant level low, performed borescope in cylinder 2 and 4, found coolant intrusion, recommend long block engine replacement which would have co"

— 2019 FORD MUSTANG owner · ENGINE · Filed 12/02/2025

"On Repair Order #:[XXX] at Lorenzo Ford, the dealership technician documented the following: “Verified customer concern, DTC P0304 perform pinpoint test, inconclusive, perform coolant pressure test and found coolant intrusion into cylinder 4."

— 2019 FORD MUSTANG owner · ENGINE · Filed 08/04/2025

All reports filed by vehicle owners directly with the U.S. Department of Transportation.

📊 Complaint Trend by Model Year

2

'19

Common Causes on FORD MUSTANG

Based on NHTSA complaint component analysis for this vehicle.

ENGINE 100%

What To Do Next

1
Check for recalls on YOUR VIN
Go to nhtsa.gov/recalls and enter your VIN. If your vehicle is covered, repairs are free.
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.
3
Compare repair quotes
Get 2–3 quotes. Dealer vs. independent shop prices often differ 30–50% for the same repair.

Frequently Asked Questions

What does P0304 mean on a FORD MUSTANG? ▾

P0304 indicates: Cylinder 4 Misfire Detected. This is a ignition system code. 2 FORD MUSTANG owners have reported this to NHTSA.

What are the most common causes of P0304 on FORD MUSTANG? ▾

Based on 2 NHTSA reports, the most commonly cited components are: Engine. These percentages are based on the component field in owner complaints.

Is P0304 serious on my FORD MUSTANG? ▾

Of 2 NHTSA reports for this code on FORD MUSTANG, none involved a crash or fire. However, any diagnostic code should be evaluated by a qualified mechanic.

What should I do if my FORD MUSTANG shows P0304? ▾

1) Check for recalls on your VIN at nhtsa.gov/recalls. 2) Get a professional diagnosis — a code alone doesn't identify the exact failed part. 3) Get 2-3 repair estimates to compare.