Hey need some help here.

Rzr Started idling high. Starting hard on first attempt. second attempt starts and idles correctly. Once you Tap the throttle the engine revs to 3300-4500 RPM and will not Return. If you tap the pedal again the engine will return to idle. I have Removed the air filter and confirmed the butterflies are returning closed. There are NO engine mods. completely stock. NO fault codes. I have made sure there is some free play in the throttle cable and no difference. Where should I go from here?????