Oil light flicker

Probably is a worn bottom end, but I would pull the sending unit and screw in a gauge to see what the real pressures are? If they are lower than say 10-15PSI at idel then just go with a heavier oil for now. If you live in a cold climate then do a 20-50, if it is warm all the time do straight 50.

Also if the pressures are OK, then you ould have a poor ground or a loose wire to the sender, or even a bad sender.