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Obd P0304

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Old Sep 6, 2006
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fondahonda is an unknown quantity at this point
Obd P0304

no 4 miss fire
cleared it once and came back two days later
where do I start
checked the plugs seemed to be OK nuthin funky
Coil?
injector?
scan?
what?
thanks for all the great info you guys put up for us green horns
fondahonda
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Old Sep 6, 2006
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Found this: http://www.obd-codes.com/trouble_cod...e-detected.php

P0304 Code - Cylinder #4 Misfire

Technical Description

Cylinder #4 Misfire Detected
What does that mean?

A P0304 code means that the the car's computer has detected that one of the engine's cylinders is not firing properly. In this case it's cylinder #4.
Symptoms

Symptoms may include:
  • the engine may be harder to start
  • the engine may stumble / stumble, and/or hesitate
  • other symptoms may also be present
Causes

A code P0304 may mean that one or more of the following has happened:
  • Faulty spark plug or wire
  • Faulty coil (pack)
  • Faulty oxygen sensor(s)
  • Faulty fuel injector
  • Burned exhaust valve
  • Faulty catalytic converter(s)
  • Running out of fuel
  • Poor compression
  • Defective computer
Possible Solutions

If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.
If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.
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Old Sep 6, 2006
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fondahonda's Avatar
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From: the woodlands, Texas, US
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fondahonda is an unknown quantity at this point
it only idels rough on cold starts
after warm up no symtoms
leaning to the coil pack or injector
how would I check either of those components?

Last edited by fondahonda; Sep 6, 2006 at 06:14 PM.
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Old Sep 6, 2006
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easy way to figure it out is swap the coil from cylinder 4 to cylinder 3 or whatever cylinder, clear the code and when it comes back if the misfire is on another cylinder then the coil is defective. if the misfire stays on the same cylinder, do the same with the injector or test the resistance of the injector.
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