I started getting the exact same thing this morning, except mine was going nearly exactly from 1500 to 2000 RPMs, drop back to 1500 and surge to 2000, over and over this morning.

The throttle reset helped, mildly, but idle is still at least 1500 RPM.

I am going to try a few things tonight, just wanted to see if anyone else could chime in...

Thanks!