Q: Check engine light on - persistent misfire 2008 Honda fit

asked by on

code po304 indicates that cylinder 4 had too many misfires within a predetermined period of time

My car has 135000 miles.
My car has an automatic transmission.

Hello - the P0304 indicates, as you state, a persistent misfire on cylinder 4. This could be due to a bad plug or coil on that cylinder, or a clogged or leaky fuel injector, causing the misfire. "Reading" the color of the spark plug"on this cylinder MAY provide some clue as to a fuel issue (black/brown soot means too much fuel - leaky injector; white may mean not enough fuel - clogged injector). If you need to replace coils, make sure you replace all of them, and you get the same supplier for all 4 (Denso or Hitachi) - the ignition systems on this one are a bit touchy for matching replacement parts. Replacement spark plugs are less sensitive to this. I would recommend an engine inspection by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Check engine light on - persistent misfire 2008 Honda fit

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: grinding noise when braking in cold temps and shifting is difficult

What you are feeling sounds like normal anti-lock brake (ABS) operation. The ABS system is designed to prevent the wheel lockup when the brakes are applied firmly or is on a slippery surface. To accomplish this, the ABS module...

Q: Car is not firing on the first two cylinders

This is generally related to spark problems when it is more consistent. Spark related problems generally will result from things like ignition coils, crankshaft position sensor, spark plugs, spark plug wires or ignition modules not working properly. As you know,...

Q: Why would my check engine light come on in my 2005 Honda Fit after it was serviced

Hello. It is not normal for the check engine light to come on after being serviced. Either something was not installed correctly or one of the parts is wrong. It may also be something completely different. I usually start by...

Related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...