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Fishtail

To lose traction with the rear wheels, allowing them to uncontrollably slither from side to side.

Fishtailing

When a vehicle's rear end swings back and forth to the right and left.

FISR

Fast idle solenoid relay.

Fit

The range of tightness or looseness that results from the application of a specific combination of tolerances in mating parts.

FITS

Fast idle temperature sensor.

Fitting

1. An accessory such as a locknut, bushing, or other part of a wiring system that is intended primarily to perform a mechanical, rather than an electrical function. 2. A hose end that is designed to mate with a mechanical part. 3. The term applied to all plumbing connections on the vehicle.

Five-point Seat Belt

A safety-belt system with two lap belts and two shoulder belts with a single buckle.

Five-window Coupe

A coupe body having five windows; two in the doors, two in the rear quarter panels, and one in the rear.

Fixed Caliper

A disc-brake caliper that does not float or slide, rigidly mounted to the steering knuckle, spindle, or control arm, having one or two pistons on each side of the disc.

Fixed Rotor

A rotor that has the hub and rotor cast as a single part.

Fixed Seal

A seal for a caliper piston that is installed in a groove in the caliper bore and that does not move with the piston.

Fixed Tappet

A solid valve lifter or cam follower.

Fixed-caliper Disc Brake

A brake system with the caliper attached to the mounting bracket and pads that adjust themselves to rotor position and thickness.

Fixed-orifice Tube

A refrigerant metering device, used at the inlet of evaporators, to control the flow of liquid refrigerant allowed to enter the evaporator.

Fixed-orifice-tube, Cycling-clutch System

An air-conditioning system having a fixed-orifice tube as a metering device and a thermostat-controlled cycling clutch as a means of temperature control.

Fixed-type Constant Velocity Joint

A joint, found on the outer ends of the derive shafts of FWD vehicles, that cannot telescope or plunge to compensate for suspension travel.

FJS

Floor jet system.

Flame Cutting

Using a welding torch fitted with a cutting head to cut metal.

Flame Front

The leading edge of an air/fuel mixture during combustion.

Flame Harden

To heat-treat metal to increase its surface hardness and wear resistance.