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Failing spark plugs in your Mini are an inexpensive and easily-fixed repair. However, if left ignored, it can cause dire consequences for your vehicle. The spark plug is responsible for producing the spark needed to ignite the mixture of air and fuel inside your engine. If they fail, your Mini’s engine will not start or run properly. Most owner’s manuals will recommend you change your spark plugs ever 60,000–100,000 miles, but keeping track of mileage between replacement can often be tricky. Let’s discuss some of the signs and symptoms of failing spark plugs.

Signs and Symptoms of Spark Plug Failure

As spark plugs need to continually produce ignition to keep the combustion cycle in motion, when they start to fail, the overarching theme of your driving experience will be rough idling, poor acceleration, lowered performance, poor gas mileage, and misfires. Let’s take a closer look at each of these points.

1. Ignition Misfire

The symptom which bad spark plugs are most synonymous with are ignition misfires. These misfires occur when the fuel isn’t correctly ignited. This will cause rough running that is most noticeable when idling, struggle accelerating, and lowered fuel efficiency. Regular misfires may also trigger the check engine light, but more on that later. When the misfires become severe enough, you will start to physically feel the difference and even hear it, too.

2. Check Engine Light

The check engine light is triggered by your Mini’s main computer, the ECU, which will pick up on the frequent misfires and trigger the check engine light to illuminate. When it does, it will also send out error codes which can be read using a diagnostic tool known as an OBDII scanner. You or your mechanic can utilize equipment to make sense of the codes to begin proper repairs.

3. Rough Idling

When misfires become frequent because of bad spark plugs, the unburned fuel can sometimes fool your Mini’s O2 sensor. This can cause the sensor to make incorrect readings, resulting in a lean air/fuel mixture. This will make your Mini run more roughly and will also contribute to even more misfires.

4. Difficult Acceleration

Due to the O2 sensor being faulty, the lean mixture of air and fuel as well as frequent misfires will make the extra “oomph” needed from the engine to accelerate a challenge, and you will likely notice that is harder to increase your speed, as if your car is sluggish.

5. Trouble Starting

As the spark plugs are essential to start your engine, if they are on the fritz, you’ll likely find your Mini is tricky to start, maybe needing several turns of your key before the engine turns over.

6. Low Fuel Efficiency

To achieve maximum miles per gallon, your Mini needs all of its parts to be working in perfect order. Therefore, with the spark plugs not doing their bit, your engine has to compensate in other ways, resulting in increased fuel consumption.

A Word of Warning

While misfires caused by failing spark plugs may only produce minor symptoms to start, it is important to never ignore the problem. Seek remediation quickly. Misfires can lead to unburned fuel exiting your exhaust pipe. This fuel is full of harmful acids and other nasty chemicals, which can damage your exhaust system, including very expensive parts such as your catalytic converter.

Repeated, severe misfires also put undue strain on your engine and its connected systems. This can lead to the accelerated wear of parts and even irreversible engine damage, in rare cases.

Spark plugs are one of the most inexpensive parts to purchase, costing as little as $2. They can be replaced at home or by a mechanic in under an hour. So, there’s really little excuse for putting the expensive components of your Mini at risk for even a short period of time over a $2 part.

Autowerks

If you are a Texan living in or around Brenham, Bryan, Caldwell, Madisonville, Navasota, or College Station, TX and need your Mini’s spark plugs replaced, then come into Autowerks. We are specialists in European cars and each job is carefully executed by our experienced technicians with the newest tools and technology. We have been in business since 1975. So, call our helpful service team today to book your appointment.