error: cannot find symbol В методе класса

Очень нужна помощь. При компиляции программы выдает ошибку:

error: cannot find symbol o

Что можно сделать? Ниже мой код:

import java.lang.Math;

public abstract class Car{
    private String name;
    private String make;
    private double fuelLevel;
    private int horsepower;
    private boolean previousUpgrade;
    protected final double MAX_FUEL_LEVEL = 100;

    //Constructor
    public Car(String name, String make, double fuelLevel, int horsepower, boolean previousUpgrade){
        if (fuelLevel > this.MAX_FUEL_LEVEL){
            fuelLevel = this.MAX_FUEL_LEVEL;
        }
    }

    // Methods
    public String toString(){
        return "Car named: " + name + " , Make: " + make + " , Fuel Amount: " + Math.round(fuelLevel) + " , HP: " + horsepower;
    }
    public boolean equals(Object o){
        if (this.name == o.name && this.make == o.make && this.horsepower == o.horsepower){ //ОШИБКА Car.java:23: error: cannot find symbol
            return true;
        }
        else{
            return false;
        }
    }
    public void upgrade(int horsepower, boolean previousUpgrade){
        if (previousUpgrade == false){
            if (horsepower < 200){
                horsepower = horsepower + 100;
            }
            else{
                horsepower = horsepower + 50;
            }
            previousUpgrade = true;
        }
    }
    public abstract void race(Object Car);

    // Getters, Setters
    public String getName(){
        return name;
    }
    public String getMake(){
        return make;
    }
    public double getFuelLevel(){
        return fuelLevel;
    }
    public int getHorsepower(){
        return horsepower;
    }
    public boolean getPreviousUpgrade(){
        return previousUpgrade;
    }
    public double getMAX_FUEL_LEVEL(){
        return MAX_FUEL_LEVEL;
    }

    public void setName(String name){
        this.name = name;
    }
    public void setMake(String make){
        this.make = make;
    }
    public void setFuelLevel(double fuelLevel){
        this.fuelLevel = fuelLevel;
    }
    public void setHorsepower(int horsepower){
        this.horsepower = horsepower;
    }
    public void setPreviousUpgrade(boolean previousUpgrade){
        this.previousUpgrade = previousUpgrade;
    }
}