When you're driving at high speed and you begun to notice that your car engine sounds rough it is not normal.
If it's not normal then what causes the problem?
Usually, rough sounds from your car engine when reaches a high speed is an indication of spark plugs or spark plugs wires problem.
As you can see, sparks plugs fires more frequent when you drive fast. Also, when your car is in high speed, your car spark plugs and spark plugs wires are being put to a maximum use. With all this been said, if your car has a failing spark plugs or spark plugs wires, your car engine starts to sound rough and the sound is mostly noticeable at high speed.
This kind of problem is usually corrected by replacing your car spark plugs and spark plugs wires.
Any auto parts has an available spark plugs and sparks plugs wires that you can buy as a replacement parts for your car engine and its easy to install, just refer to your vehicle repair manual if you need help or, you may want to bring your car to a reputable shop for servicing and also for complete analysis on your car.