New Spark Plugs – All Spark Plugs Need To Be Changed Sooner Or Later

New Spark Plugs - All Spark Plugs Need To Be Changed Sooner Or Later
New Spark Plugs - All Spark Plugs Need To Be Changed Sooner Or Later

New spark plugs need to be installed because, spark plugs, do NOT last forever.

One thing to keep in mind with respect to performance claims is that, spark plugs create horsepower. That is false.

The spark plug only ignites what is already in the combustion chamber. So, if there are any power gains to be had, they will be the result of, reduced engine misfires.

New spark plugs, maintain peak engine performance and efficiency. Every engine will misfire occasionally. But, as the number of misfires per mile goes up over time; it increases exhaust emissions, wastes gas and reduces power.

All 1996 and newer vehicles have an OBD-II onboard diagnostic system, that tracks ignition misfires. When the rate of misfires exceeds a certain limit it; will cause emissions to increase 50% over baseline levels. As a result, illuminating a warning light.

Plug Comparison
Plug Comparison

So, on older vehicles, installing plugs at the recommended service intervals for preventive maintenance; will reduce the risk of misfires and maintain peak engine performance.

Why Install New Spark Plugs

Installing new plugs, is not a cure-all for driveability and emissions problems. But, in most cases, can make a significant improvement.

New spark plugs, improve cold starting. Bad plugs are often responsible for many cold weather “no start” service calls. Many times the battery has been run dead, while cranking the engine; because the plugs would not fire. When the old plugs are removed and examined, they are often found to be worn or dirty. Dirty spark plugs can cause fouling, which results in misfiring.

New spark plugs, reduce the voltage requirements on the ignition system; which decreases the chance of misfire, while leaving more amps for the starter and injectors.

Wet fouled plugs, can also prevent an engine from starting. But, in many instances the fouling problem, has nothing to do with spark plug wear or neglect.

On fuel injected engines, wet fouling is less of a problem; but can happen, if a cold start injector leaks. Or, there is a fuel calibration problem that creates, an overly rich startup mixture.

Also, new spark plugs, minimize the risk of catalytic converter failure. A single misfiring plug, can dump enough raw fuel into the exhaust to, overheat and damage the converter.

Excessive Oil Fouled Spark Plugs
Excessive Oil Fouled Spark Plugs

The presence of higher than normal quantities of unburned fuel in the exhaust; will cause the operating temperature of the converter to soar; which may lead to a partial or complete meltdown of the converter.

This, in turn, may form a partial restriction or complete blockage in the exhaust. As a result, creating enormous backpressure and chokes off the engines ability to exhale. The engine may lack power, especially at higher speeds, and deliver terrible fuel economy.

Signs You May Need To Install New Plugs:

  • Engine has a rough idle.
  • Having trouble starting your engine?
  • Your engine misfires.
  • Engine surging.
  • High fuel consumption.
  • Lack of acceleration.

So, replacing spark plugs early makes sense.

The recommendations for spark plug replacement intervals tend to be, overly optimistic. If you’ve already got 80,000 miles on a set of 100,000-mile plugs, they’re 80 percent worn. They are already taking a toll on engine performance and gas mileage. Worse yet, after that many miles, spark plugs have a tendency to, seize in the cylinder head.

What If A Spark Plug Breaks ?

Removing a seized plug can be a costly job. Especially if the threads in the cylinder head are damaged in the process. When you consider the gas mileage loss and the possibility of seized plugs, early replacement makes sense.

Removing A Seized Spark Plug Can Be A Costly Job
Removing A Seized Spark Plug Can Be A Costly Job

Here’s the trick on how to punch that porcelain center out, without getting porcelain in the cylinder. ( This does not always work, but it may save you time and money. )

Find The Correct Size Easy Out And Remove The Broken Piece
Find The Correct Size Easy Out And Remove The Broken Piece

Turn over the engine and let the cylinder compression do the work for you. If you are lucky you will see the porcelain center POP out of the body. This should leave the metal threads and base of the plug inside the plug hole. Depending on the plug and hole size,  find the correct easy out and remove the broken piece.


In general, it’s best to install new spark plugs, as part of preventative maintenance; based on manufacturer’s specifications. This can help save you from costly repairs; as driving with misfiring plugs, could put undue stress on your vehicle’s catalytic converter.

Thank You !