Neutral (gear). Neutral is actually not a gear. When your vehicle is in neutral, the gearbox and engine are completely disconnected. Thus, your car is able to roll freely whether the engine is on or off.

An acronym for Oxides of Nitrogen, a primary emission produced in the combustion chamber under high temperatures when nitrogen combines with oxygen. Oxides of nitrogen contribute to the formation of smog.

A fuel octane rating measures a fuel’s resistance to knocking or pinging.

An instrument measures levels of a certain system and provides a visual key for those levels. For instance, the gas gauge in your car measures the fuel level, while the temperature gauge indicates the engine temperature.

The intake manifold goes between your vehicle’s fuel system and the cylinder head(s).

A leakdown test is used to find excessive wear in an engine. When a technician performs a leakdown test on your vehicle, each cylinder is tested to see how well it holds pressure. If a cylinder is unable to hold

Liability insurance is coverage only for damage that you inflict on other people or their possessions. It does not cover theft or damage to your vehicle.

Limited-Slip Differential (LSD). An LSD senses the slippage of each wheel it sends power to and redirects power to the wheel with the most grip. Many high-performance vehicles have LSDs.

Hydrocarbons (HC) are essentially fuel which was not burned during the combustion process or which has escaped into the atmosphere through fuel evaporation. The main sources of incomplete combustion are rich air/fuel mixtures, low engine temperatures and improper spark timing.

When your car is on but not moving, and you are not touching the gas pedal, it is idling. For instance, when you are waiting at a stop light, your car is idling.

This is a special kind of circuit found in a carburetor that only operates when the engine is at an idle.

The condensor soaks up excess electrical energy in an ignition system that has points. This prevents that extra energy from jumping across the points when they first open and close.

Part of the ignition system which instructs the coil to send voltage to the distributor.

Part of the ignition system which instructs the coil to send voltage to the distributor. They do this by opening and closing, which turns on and off a circuit.

This is the switch where you insert the key that starts your vehicle.

The ignition system contains the components that supply spark to your vehicle’s spark plugs. These include the battery, the coil, the distributor (including the cap and rotor), the spark plug wires, the ignition module, and the spark plugs themselves. Older

Timing refers to when the spark ignites the air/fuel mixture. Timing needs to be set exactly right for an engine to run correctly.

The heater ducts are the tubes that connect the heater fan to the vents in your vehicle’s dashboard.

The heater fan is the interior fan that controls the speed of air being introduced into the interior.

The heating system warms the air brought into a vehicle’s interior. The heating system is connected to the cooling system and consists primarily of the heater core, heater valve, and, if equipped, a climate-control system.