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Mike V.
Mike V., Technician
Category: Kia
Satisfied Customers: 25682
Experience:  I have 25 years experience working on cars. I am also a factory trained Subaru and Nissan Tech.
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2011 rio started running rough. The roughness started before

Customer Question

2011 rio started running rough. The roughness started before and I replaced the plugs. It ran smooth for about a week then the roughness returned. I replaced the coils. About 3 months later it is running rough again. P0300, P0301, P0302, P0303 codes show. What is going on? No power and running rougher than a model T in need of a valve job...
Submitted: 2 years ago.
Category: Kia
Expert:  Mike V. replied 2 years ago.

Hi there,

Did you use aftermarket ignition coils on it?

Customer: replied 2 years ago.
Expert:  Mike V. replied 2 years ago.


I would start by spraying some water on the coils with the engine running to see if they are arcing. This would be the most common issue to happen with these. If you don't see any sparks arcing then you might want to check compression, it is possible the timing belt has jumped time and could be causing these misfires. I mean since basically all but one is misfiring it could very well be the issue. I would start by checking the coils first though.

Please let me know if there is any more I can do to help you from here.

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Customer: replied 2 years ago.
Do I just take off the cover and spray the water on them and observe or must I pull one from the plug?
Expert:  Mike V. replied 2 years ago.

You can just pull the cover, then use a spray bottle and spray them sitting right there with the engine running. It will either start running rougher, or you may hear snapping, the snapping is usually a spark arcing off the coil.

Customer: replied 2 years ago.
Okay. Thanks.
Expert:  Mike V. replied 2 years ago.

You are very welcome, please let me know if I can do anything else to assist!

Also, please remember to rate my answer, thanks so much!