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Q: Failed emmissions test

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I went to get my emissions checked today and my car failed the test. The hydrocarbons read 9.0 pm which was off the chart and the CO% was 361. Do you know if new plugs and wires would bring down the numbers enough to pass the test? Is there anything else I could replace to help pass the test?

Hello. If the plugs and wires have not been replaced for several thousand miles, then replacing them may indeed help lower emissions levels. New plugs and wires can help produce a stronger spark, which will result in a cleaner burning fuel mixture. However, due to the excessively high hydrocarbon levels, this alone may not be enough for the vehicle to pass the test. A full tune-up, along with a thorough inspection of the ignition and fuel systems, may help lower emissions levels further, perhaps enough for the vehicle to pass. I would also recommend checking the condition of the catalytic converter, as a faulty catalytic converter can cause the vehicle to produce higher emissions as well, particularly CO. If you need help, a certified technician from YourMechanic can replace the catalytic converter for you.

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