I have a 2011 Mule 4010 (gas). It starts and idles fine. However, after the engine warms up (runs for about 15 minutes) it starts "surging". The mule still idles fine, but if I'm driving, I get this weird issue. I've attached a video.

Here are the things I've addressed:
Changed oil
Changed fuel pump filter (at bottom of tank)
New air filters
New plugs
Removed crankcase exhaust from throttle body

Any help would be greatly appreciated.