A half shaft is a drive axle that extends from a transaxle or differential to one of the drive wheels. There are two half shafts per drive axle, one for each wheel, each doing "half" the job.

Constant velocity (CV) joints are located at both ends of a half shaft and their purpose is to transfer the torque from the transmission to the drive wheels at a constant speed while accomodating the up and down movement of the suspension. The inner CV joint connects the shaft to the transmission and the outer CV joint connects the shaft to the wheel.

The muffler follows the catalytic converter and absorbs sound to help quiet load exhaust. It is followed by the exhaust pipe which is the final exit point for exhaust gas from the vehicle.

During the power stroke, just before the piston reaches top dead center, the spark plug fires and ignites the compressed air-fuel mixture. The resulting expansion due to combustion pushes the piston back down the cylinder toward bottom dead center.

The ignition coil is a high-voltage transformer made up of two coils of wire. The primary coil winding is the low-voltage winding and has relatively few turns of heavy wire. The secondary coil winding is the high-voltage winding that surrounds the primary and is made up of thousands of turns of fine wire. Current flows from the battery through the primary coil winding which creates a changing magnetic field inside the secondary coil. This induces a very high-voltage current in the secondary coil which it feeds to the distributor.