airplane wobble in flight.

[slo]

Hello all, you will think I am crazy but I swear my airplane wobbles when in cruise. Its very slight and you can only feel it if it is dead calm, but it feels like an auto pilot continuously correcting, only I don't have an auto pilot. None of the flight controls appear to be moving. It feels like the rudder is doing it however the rudder pedals are not moving at all and holding pressure on the pedals doesn't make it go away.

Any thoughts?

 

[kf6iat]

 

[slo]

 

[kgreen]

 

[Tweety]