Recommended videosChange & Inspect Spark Plugs
What are the Symptoms of a Bad Spark Plug?
Diagnosing a bad spark plug can be difficult, as it usually shares symptoms with many other potential problems, but there are some things you can look for.
- Higher than Normal Fuel Consumption
- Lack of Power When Accelerating
- Engine Idles Roughly or Struggles to Start
- Engine Sputters or Misfires While Accelerating
While a vehicle is running, each spark plug in the engine is firing hundreds to thousands of times per minute. Over time, this wears on the plug, leaving it potentially unable to create a spark. There are a few different types of spark plugs, including copper, platinum, and iridium. The lifespans of each can vary greatly. Generally, standard copper plugs will last around 35,000 km, with platinum plugs lasting around 100,000 km, and iridium plugs lasting up to 150,000 km.
A bad spark plug could mean that the engine has cylinders that are not firing, causing it to sputter and run poorly. This greatly affects the vehicle’s efficiency and performance.
It is generally recommended that you replace spark plugs with those made by the vehicle’s original parts manufacturer. Often times this means AC Delco for GM engines, Autolite for Ford engines, Champion for Chrysler engines, and NGK or Denso for Asian makes. Consult your vehicle’s owner’s manual for recommended spark plug replacement specifications.