Question

How do I determine which of these possible causes for code P0304 on a 2008 Hyundai Accent 1.6L is the actual problem?

Answer 1

There are several ways to test for this. First, with the engine running, try spraying some water on the ignition coils. Usually if one is bad there will be arcing and the engine will begin to run rough.The other option to use would be compression test. This will tell you if the engine has an internal issue.

Answer 2

P0304 HYUNDAI - Cylinder 4 Misfire Detected

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