A set of spark plugs usually requires replacement every 20,000–30,000 miles (32,180–48,270 Km) for mostpre-1996 cars with electronic ignition systems, or every 15,000 miles (24,135 Km) on turbocharged vehicles with electronic ignition, depending on your style of driving. 1996 and newer require spark plugs around 80,000-100,000 miles.

Spark Plug Diagnostic Chart