Engine Electrical
Spark Plugs
Spark plugs fire the air and fuel mix in each cylinder, and worn plugs hurt starting, power and fuel economy. We list 37 spark plugs from $2 to $32 by Bosch, AC Delco, NGK, SKP and Denso, with fitments for Chevrolet Malibu, Camaro and other Chevrolet models from 1979 to 2021.
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When to replace spark plugs
Follow the replacement interval in your owner's manual. Many modern engines use long life plugs, while older engines need more frequent changes. Signs of worn plugs include hard starting, rough idle, misfires, weak acceleration and lower fuel economy.
When you remove old plugs, look at them. Oily, sooty or damaged plugs can point to engine problems that a new set will not fix.
Iridium, platinum or nickel
Electrode material affects how long a plug lasts. Nickel plugs are affordable but wear fastest. Platinum lasts longer, and iridium is used in many newer engines for long service life.
Use the plug type and heat range the engine maker specifies. Fitting a different type does not usually add power and may shorten the replacement interval. Sets of 4 and 8 plugs are available.
Installation tips
Work on a cool engine, especially with aluminum cylinder heads. Check the gap against the spec, but avoid prying on fine iridium or platinum tips. Many plugs come pre-gapped.
Start each plug by hand to avoid cross threading, then tighten to the torque spec. Follow the plug maker's guidance on anti-seize, since some plugs have plated threads that do not need it. Reconnect coils or wires to the correct cylinders.
Spark Plugs questions
Do new spark plugs need to be gapped?
Check the gap against your engine's spec even if the plug is pre-gapped, since gaps can shift in shipping. Use a gap tool that will not damage fine wire tips.
Can I use iridium plugs in place of copper or nickel plugs?
Often yes, if the plug maker lists it for your engine with the correct heat range. Some performance engines specify a particular type, so check the fitment table.
How tight should spark plugs be?
Tighten to the torque spec for your engine and plug type. Too loose can cause overheating and compression loss, and too tight can damage threads in the cylinder head.