High RPM issues in any car are often due to spark plugs. Have yours been changed? It's an expensive thing to do "just because" (the iridium plugs are super expensive compared to normal plugs), but if they have not been removed since the car was manufactured, now is the time to change them before they weld to the heads.
EGR valve issues are also common, but I doubt that's your problem since EGR lift at high speeds is only slight compared to low speeds.
EGR valve issues are also common, but I doubt that's your problem since EGR lift at high speeds is only slight compared to low speeds.
