DF-90 Surging 3/4000 rpm

[dalealan]

My DF-90 has begun to surge betweeen 3000/4000 rpm varying up to 400 rpm but usually about 200 rpm. Not the end of the world but is noticeable. 2011 year model,never any problems. Many trips but only
about 2 hours each trip. Less than 200 hrs total, well maintained, looks new inside and out. It appears to me to be a fuel issue. I have never run any fuel treatment through tank, fuel has always been fresh. Have changed the plugs once even they looked new.
Could this be as simple as adding fuel treatment to my tank or is it something more serious? Have a Racor see/through filter, changed once and no water or trash has ever been visible.
Any Ideas?
Dale

[Murray]

Have you checked all your sensor connections for tightness/frayed wires? Maybe your ECM is getting a fluctuating signal, not enough to throw a code but enough for the ECM to think you are increasing/decreasing throttle. Certainly can’t hurt to add a fuel conditioner, easy and cheap.