1. Engine Power: The 1998 Plymouth Neon was equipped with a 2.0-liter, four-cylinder engine that produced 132 horsepower and 130 pound-feet of torque. This amount of power may be insufficient to propel the vehicle to speeds higher than 80 mph, especially if there are additional factors such as weight or aerodynamic drag.
2. Transmission: The 1998 Plymouth Neon was available with either a five-speed manual transmission or a three-speed automatic transmission. The automatic transmission may have a higher gear ratio for fuel efficiency, which could limit the vehicle's top speed.
3. Speed Governor: Some vehicles are equipped with a speed governor that limits the maximum speed the vehicle can reach. This is done for safety reasons or to comply with regulations in certain jurisdictions. It is possible that the 1998 Plymouth Neon has a speed governor set to 80 mph.
4. Aerodynamic Drag: The 1998 Plymouth Neon is a compact car with a relatively boxy shape. This shape can create significant aerodynamic drag at higher speeds, which can limit the vehicle's top speed.
5. Mechanical Issues: There may be mechanical issues with the vehicle that are preventing it from reaching higher speeds. These issues could include problems with the engine, transmission, or driveline.
It is recommended to have the vehicle inspected by a qualified mechanic to determine the specific reason why it is not going faster than 80 mph.
