I will provide an honest answer. I trust this will be appreciated. Please remember that a low rating PUNISHES me for being honest and that I receive nothing for my time until a positive rating is clicked.the problem is leaky valve seals. this is VERY common with your engine. They all start to do this as time / mileage accumulates.
you will need to have the valve seals replaced.Please let me know if you have further questions. Please do not forget to click a positive rating as this is the only way I receive credit for my answer, thank you. Best wishes with your vehicle.