The engine dashboard light is on on my car. The engine vibrates and has a lack of power. The diagnostic tool show the trouble code P0304. It means that there are misfire on the cylinder number 4.
After having tested the charging circuit, I test the ignition coil on the defective cylinder with an ignition coil tester.
I who you how this tool works.
Since the ignition works well, I test the spark plug with a spark plug tester. The spark plug doesn't work. So I replace it and check that the engine works well.
The dashboard light becomes off and there isn't trouble code
anymore.

0:00 Intro and preliminary tests
1:16 Ignition coil test
4:35 Sparkplug test
5:49 Spark plug refitting and conlusion

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