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.
Code P0316
i've heard of the 5.4l's with the "cop" set up devolping moisture under a coil. if it hasn't again that is most likely the problem. to prevent this you could remove each coil and apply dielectric grease to the tops of the plugs.
Hi James Kujawski, I want to help you with your question, but I need more information from you. Can you please add details in the comment box? year, make, model, engine size?
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