should I do a engine flush on my 2007 lincoln mkz?

Yes you should. The fact of the mater is no matter how often you change your oil, or the type of oil you use, it will always leave contamination in your motor from normal vehicle operation. An easy way to tell if you have contamination is to look at your dip stick. Is the oil clean like new motor oil? Or is it dirty and black? If it's dirty and black after 250 miles after getting a new oil change, then you have contamination in your motor. If you ignore the contamination, it will settle in different parts of the motor and turn into deposits. Over time, these deposits can restrict the flow of oil which can lead to running issues, low compression, poor acceleration and rob you of gas mileage. If you use the best engine flush: https://www.protecautocare.com/motor-vehicle-care/engine-flush then your motor will be fully protected during the flush and it'll break down all the contamination in your motor down to 1/3rd of a micron. You'll experience restored power and you'll see your MPG improve to where it should be. So, yes, when you use the right product, an engine flush is good for your 2007 Lincoln MKZ.

Do not use an engine flush. The lack of lubricity in some of these products could in theory damage something in the engine. I would be especially worried about the valve train. Change your oil at the recommended intervals and you will be fine.