So.....I posted an answer here but I thought it was for a Toyota Camry, so I checked (EDIT) and put this reply. MAKE SURE THE COOLING FAN IS KICKING ON. YOU SHOULD HEAR IT WHIRRRRRR UP AT HIGH ENGINE TEMPERATURES. The little things can be overlooked so fast, it'll make someone's head spin. Also, have the Engine Coolant Temperature Sensor replaced. The connector on them can get brittle from normal heat and age, which causes a bad signal to the computer. I just might save you more money if I caught this in time. Jay