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Severity: ModerateFord

P0304 on Ford Vehicles: Cylinder 4 Misfire Detected

Cylinder 4 is misfiring. Its end or rear position makes water, oil and intake leaks common culprits. P0304 →

110Complaints mentioning the code
#1Rank among 16 brands
4.2%Share of Ford DTC complaints

In NHTSA owner complaints we analyzed for Ford, P0304 was mentioned 110 times.

Most mentioned models

Ford Escape50
Ford Edge29
Ford Fusion Hev8
Ford Fusion Energi5
Ford F-150 SUPER CREW4
Ford Fusion4

Model years mentioned

Model years mentioned – Ford P03041061113125132144151616451716181719
2006: 1 · 2011: 1 · 2012: 3 · 2013: 5 · 2014: 2 · 2015: 4 · 2016: 16 · 2017: 45 · 2018: 16 · 2019: 17

Components named in these complaints

  • Engine (101)
  • Power Train (10)
  • Engine And Engine Cooling (10)
  • Unknown Or Other (7)
  • Fuel/propulsion System (4)

Reports with a crash: 0 · fire: 1 · injuries: 0

Often appears together with

Possible causes

  1. Failed coil or coil boot on cylinder 4, often from water or oil sitting in the plug well28%
  2. Worn or cracked cylinder 4 spark plug25%
  3. Vacuum leak at the end intake runner, intake gasket or nearby PCV connection14%
  4. Clogged or leaking cylinder 4 fuel injector13%

P0304: Diagnosis step by step →

Related codes

Source: NHTSA Complaints API (US government open data), analyzed by DTC mention.