FACSAria unstable drop 1 and gap

Hello,
I was wondering if any Aria users have experienced unstable drop 1 and
gap even with the Sweet Spot on.  I use a 100um nozzle.  I have
de-bubbled the filters, cleaned the flow cell with contrad 70, sonicated
the nozzle and changed the O-ring.  I have also tried using a different
100um nozzle and a 70um nozzle.  The gap still fluctuates between 2 and
20 and the drop 1 goes between 100 to 300.  The numbers just bounce
everywhere.  Any suggestion for why this is happening and any solution?
Thanks,
Alice