Strange slow elevator drift and violent elevator bobble

[FlyBri3]

I have been working on this issue for a while now and can't figure it out! For starters I have savox 1250mg cyclic servos and a standard BX FBL unit. But since the issue is about my Atom I figured I would post here.

About 6 months or so ago all of a sudden in a hover I noticed I was having a slow ELE tail drift. The heli would be stable as can be hands off in a hover but after a few seconds would slowly start to drift back. Guessing Vibration somewhere? I changed all bearings shafts balanced blades checked for anything bent. Finally it was suggested that I reset my BX to factory, so I did and reprogrammed it and while I was doing that I figured I would lube and replace the dampers. Tail drift went away for a bit but came back and I also had a violent head bobble that wasn't there before with the same settings in my FBL unit that I had before. I rebuilt the head a few more times thinking I may have done something wrong, but No dice! Elevator/ head bobble remains! I finally turned my pot 1 gain down almost half way from center to 0 that took the head bobble out but now the heli just drifts and does not feel locked in!

I did find My motor shaft and pinion were loose so I have new Bearings ordered thinking that may be the cause of my VIbe issue. If not then maybe my Elevator servo is going bad? I just don't have a clue! Any Ideas on possible causes?

[FlyBri3]

At my field a buddy of mine noticed my elevator servo lead had a small tick in the wire just out of the receiver plug. I cut an inch off and replaced it with a new plug. That seems to have helped the tail drift for now and also allowed me to turn the collective gain up just a bit without major ELE bobble! Still not 100% but little better. So guess I'm on the rite track.