Purcell: We'll keep you moving

Basic Ignition Parts

Spark Plugs: Spark plugs are good indicators of engine condition. Removing and inspecting spark plugs tell us a lot about how well the engine is running and what may be causing problems.

All spark plugs should be removed and checked every 30,000 miles - even if your car is "low maintenance" - you're told to change spark plugs at 100,000 miles. This prevents the plugs from seizing in the block, causing expensive repairs down the road.

Distributor Cap & Rotor: Both the distributor cap and the rotor are usually plastic and, thus, deteriorate with age and use. Cracks may develop, allowing moisture in. The metal contacts on both can then corrode, causing misfiring.

Spark Plug Wire Sets: Spark plug wires have become less of a problem than before. New materials and sizing have reduced failures. Electronic ignitions have increased operating ranges. Now these should be tested for proper resistance before replacement. They are no longer replaced routinely with the cap, rotor and plugs.