Cam757 wrote on Feb 7^th, 2019 at 2:14pm:

Try engaging it after you lift off rather than on the take-off roll

So for me, I advance my throttles to 100%, than hit the EPR button.  EPR should roll the thrust setting back to the SEL temp.

I often press the EPR button at the start of the takeoff roll, without using the throttles. Other times, I advance the throttles slowly to 100%, then press the EPR button. Either way, the EPR engages for me.

An addition to my previous post.....

Yesterday, after advancing the throttles to 100%, and upon reaching 80 knots, I pressed the EPR button, but it failed to engage! It only engaged after takeoff, and at 400ft AGL, I pressed the AP button, then LNAV, and VNAV (it was turning on the VNAV that engaged the EPR). This was in the newly installed 757 III freighter for FSX-SE. I'm just telling which version it happened in, because I generally find that the performance of the 757-III is the same across all platforms (FSX/SE/P3D3/P3d4), of which all are istalled on my computer, but with FSX, I can't activate SP2, or Acceleration in Windows 10 at the moment.

I must admit that I switched to turning the VNAV, and LNAV on after switching the AP on, due to an earlier problem, where having them on, and after takeoff turning on the AP, the 757 turned them off, and used VS Hold, HDG Hold instead. I haven't gone back to the old way, but I really should have (I got into a different habit ). That could be the reason why the EPR isn't engaging!

There is supposed to be a way to get it to activate, but I've tried it quite a few times without any success.

Any final word on EPR engagement on takeoff roll?
it seems to me that EPR works fine of first takeoff, then if you try another take off it will not engage. Why? Do they fixed it already after many updates?

Thanks