Highway surging idle

Good morning! The issue I'm having is with my car listed above GT. I have an intermittent problem that comes and goes. When I drive and rev it to about 3,000 to 3,500 or even past 2,500 when I push in the clutch it's wanting to hang around 2,000 rpm's. It doesn't always do it though. If it's stuck at 2,000 I can go back into gear and idle it down but as soon as the clutch is disengaged it goes back to where it was. Same thing with revving it up it drops right back. It will also sometimes hang and then drop to 1,500 and rev to 2,500 and cycle. This only happens when I'm moving. I can let it hang or surge for as long as I can with no change. The only solution I've found is to quickly shut the key off and back on. The engine starts back on its own and the issue will either go away for the rest of the drive or until I pass 2,000 again. Key thing if I come to a complete stop with it doing either the hang or the surge it will drop in rpm and die. It has zero issues at idle and no check engine light. I have noticed it seems to happen more on my drive home from work in the afternoon vs morning commute. Approximately 65 to 70° and 90-100.