oil light come on at idle, need advice Options

[Yupe7]

So before redo my timing on my Celica wanted to ask you guys that have the 5sfe engine do you or have you ran into the issue where the oil light comes one or flickers at idle (since it started will turn off under acceleration). Also the idle is a bit lower than normal.
For some backup story is swap engine got it for what it seemed to be running good but later on found it was burning oil the oil light turns on only at idle but oil was low (none on dipstick). put more oil and replaced cam seal redid timing and put it to 10 degrees for it was at 9 degrees.
Oil light comes on only when the vehicle is warm, not cold.
any suggestion thank you

thinking of two things
redoing timing and oil pressure relief valve is stuck open