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Severity: ModerateHonda

P0304 on Honda Vehicles: Cylinder 4 Misfire Detected

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

80Complaints mentioning the code
#2Rank among 16 brands
11.0%Share of Honda DTC complaints

In NHTSA owner complaints we analyzed for Honda, P0304 was mentioned 80 times.

Most mentioned models

Honda Cr-V20
Honda Odyssey19
Honda Accord15
Honda Pilot12
Honda Fit8
Honda Civic2

Model years mentioned

Model years mentioned – Honda P03042114121013414715716151719181219
2011: 2 · 2012: 4 · 2013: 10 · 2014: 4 · 2015: 7 · 2016: 7 · 2017: 15 · 2018: 19 · 2019: 12

Components named in these complaints

  • Engine (63)
  • Fuel/propulsion System (33)
  • Power Train (14)
  • Unknown Or Other (9)
  • Electrical System (9)

Reports with a crash: 1 · fire: 0 · 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.