Replacing worn spark plugs can greatly improve your engine’s performance and efficiency. Replacement intervals vary widely by car manufacturer and spark plug metal types and design. Recommended spark plug replacement intervals can range from 30,000 miles to every 100,000 miles, You will need to follow the recommendations in your owners’ manual. It’s OK to upgrade but never down grade from the manufactures factory requirements. Doing so will hinder performance and may cause issues related to sister components or the engine itself.
Spark plugs fire constantly and wear down over driving time, reducing their efficiency. Spark plug replacement can be challenging on some vehicles engines. The greatest challenges you’ll face is accessibility and sticking components such as when removing the spark plug wires or ignition coils/boots and unscrewing the spark plugs. Some spark plugs can be difficult to reach and require removal of the upper plenum/intake manifold. In these cases, a new plenum gasket will be needed. Check the Repair Guide for your specific vehicle and engine.
You may need to gap your spark plugs before installing them. Some plugs come pre-gapped, and if this is the case it will say so on the box. Otherwise you’ll need a gap tool to gap your new plugs according to the specifications in your owner’s manual. Most modern cars use plugs made from long-lasting materials, so you might only need to do a spark plug replacement once or twice over the time you own a vehicle.