Q: Car shaking, engine light and traction off. Codes P0300, P0301, P0304, and P0351

asked by on September 15, 2017

Car shaking, engine light and traction off. Codes P0300, P0301, P0304, and P0351. I replaced spark plugs like 2 weeks ago and now this is happening. I just checked them again as well the coils ans they seem to bw working just fine.

My car has 40000 miles.
My car has an automatic transmission.

Hi Getze. Thanks for contacting us tonight. The OBD-II codes you’ve indicated show that you have a series of random misfires - specifically on cylinders #1 & #4. This may be caused by the new spark plugs or the plug wires being incorrectly installed. If the plugs are not the recommended ones or not properly gaped, it can also cause this issue. I would recommend verifying that your plugs are correctly gaped as recommended by Toyota (not the spark plug manufacturer) and that each plug wire is correctly installed first. Second, you might want to read this article on the P-0300 OBD-II code, as it will list all the possible sources, so you can begin your inspection and correctly isolate the root issue.

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