I am thinking if it was lean fuel you would have already blown the motor because it sounds like this has been going on for a while. Watch the tack to see if it starts fluctuating. Check the spark at the problem rpms.
ï¿½The world will not be destroyed by those who do evil, but by those who watch them without doing anythingï¿½ Remember what He has done and remember that He is not done yet! GOD IS GOOD