power loss in flight

Maybe the spring IS pulling it...  are the throttle arms on the carbs moving after you set it where you want it?

Throttle in in center of panel. Hard to believe I changed anything, almost like a spring was changed or something ?

Is it possible the friction / throttle tightened knob held it in place and I for the first time loosened it all the way ?

Doesn’t seem likely, but what else could have changed.      Ahhhhhhh........

That's my first guess... a change in the friction of your throttle control.  

Did you disconnect the springs on the carbs?  Check how they are connected now.

Never touched the springs. I thought the friction knob was relaxed until needed to hold in power position, never considered the friction knob was to hold it from gaining rpm at low settings ?

Guess I always figured Common sense-wise the springs were to hold throttle closed,