2017 Lincoln MKZ - 2 problems

The car has started to idle a bit high and makes a noise from front passenger side and a slight vibration in steering wheel when driving at speeds up to 55. Over 55, no noise or vibration.

Maybe you should see a mechanic and describe your symptoms to him. We cannot drive your car over the internet,he can.

If your Powertrain Warranty is still in effect–as I assume that it is with a 3 year old vehicle–this problem would likely be covered by that warranty.

This is likely to be (at the very least) a wheel balance problem, but because this is a possible safety hazard, you need to have a mechanic drive it and diagnose the problem.