I asked this question in the Questions forum but received no response. Thought I'd try here. I noticed something on my Sig Fazer ( OS .52 4 stroke) that I'd never seen before. I think I have a problem but I'm not sure. I was having some idling issues and finally got it adjusted right. I was running the engine on my bench and I noticed that when I got to about 50% throttle, my control surfaces started twitching back and forth. Looking at the servos, both aileron and throttle, I could see the servo arms moving back and forth, just a little, maybe an eighth inch total.. I could see the throttle rod moving back and forth with a slight increase and decrease in RPM. So the ailerons and rudder is twitching back and forth just a little. I didnt see the elevator as it was disconnected. I thought maybe I was getting a little interference from my thottle arm connection but on the .52, the throttle arm is plastic. My servos are Futaba 3004s and I had a fully charged TX/RX. I wondering if this is a vibration that shows up when its on the bench but disappears in the air. Maybe its always been this way, I just don't know. Up until this idling problem, the plane has always flown very well. I may hook up another receiver and see what happens but I wanted you flk's opinion first. As always, thanks in advance