Chosen Solution
So this is the second iphone 6 Plus I have repaired in a row that it has had flickering bars. It doesn’t happen with any other iPhone that I repair and I’m not sure why. Any suggestions?
A common failure on the iPhone 6Plus is Touch Disease. You can go to my profile for a link to my blog post on this subject for more info. In your case, you don’t mention where this gray bar is or if there is any effect on touch functionality. If it is at the top of the screen and you lose touch, even intermittenly, then your phone has Touch Disease. If it is somewhere else, then ideally you should post a picture so that we can help you.
I don’t know if you have an iFixit wholesale account or not. Here iPhone 6 Plus LCD and Digitizer It’s a pretty good price point, for the parts you’re getting
