Spark Plug Problems: Signs Your Car Needs New Spark Plugs

Published on 30 August 2026 at 8:42 pm

Spark plugs are small parts with a big job. They create the spark that helps your engine start and run smoothly. When they become worn or dirty, you may notice your car is harder to start, uses more fuel, idles roughly, or feels slow when accelerating.

At Auto Point Plus, we can inspect your spark plugs and help you choose the right replacement for your vehicle.

Which Spark Plug Is Right for Your Car?

There are different types of spark plugs, and each one is designed for different vehicles and service intervals.

Copper spark plugs are commonly used in older cars and some performance engines. They offer good conductivity but wear out sooner than other options.

Platinum spark plugs last longer than standard copper plugs and are a popular choice for many vehicles.

Iridium spark plugs are made for long-lasting performance. They have a fine centre electrode that helps provide reliable ignition and can last up to 100,000 miles in some vehicles.

The best spark plug for your car depends on your engine and the manufacturer’s recommendations. Fitting the wrong type can affect performance and fuel economy.

Signs Your Spark Plugs May Need Attention

Worn spark plugs can cause several common driving problems, including:

Engine misfires
Rough idling
Trouble starting the car
Slow or weak acceleration
Higher fuel consumption
Check Engine light warnings

If you notice one or more of these signs, it is worth having your ignition system checked.

Can Spark Plugs Be Cleaned?

In some older vehicles or small engines, lightly dirty spark plugs may be cleaned and reused for a short time.

For most modern vehicles, replacing worn or heavily fouled spark plugs is usually the more reliable option. New spark plugs can help restore smooth performance, improve starting, and support better fuel efficiency.

If the plugs are repeatedly becoming dirty, there may be another issue affecting the engine. A professional inspection can help identify the cause.

Avoid These Common Spark Plug Mistakes

Spark plugs need to be fitted correctly to avoid damage and poor performance.

Always make sure the spark plug gap is correct for your vehicle. Be especially careful with fine-wire platinum and iridium plugs, as adjusting them incorrectly can cause damage.

Never force a spark plug into the engine. Start it by hand first to avoid cross-threading, especially in aluminium cylinder heads.

It is also important to tighten each plug correctly. Over-tightening can damage the thread or crack the ceramic part of the plug, while leaving it too loose can cause other problems.