I had a little ring...turned out to be a loose actuator valve...gave it half a turn and all was good after. Take off the heat shield, spray some lube/wd40 onto the shaft and turn on the car. Have someone stab the throttle and let off...see if you can pinpoint if its coming from there or not. If it is, take off the clip, loosen the lock nut and tighten the lever in half a turn...set the jam nut back on, put the lever back onto the shaft and put the clip back on. Rev it again and should fix it.