I wouldn't try the Bon Ami trick unless you want to seize it. Are you sure of the mileage? How thick/old was the oil in it? What did you flush it with? What grade of oil did you refill with? Lots of questions before you can expect an answer. It sounds like the old oil was heavy grade and maybe you refilled with something like 5w30. I would suggest 15w40 would be more suitable in an older engine. It's probably because you cleaned out the compression and oil rings with the flush and it will take some time to get working again.
My 2013 auto D4D DC SR5, prefilter, 3" exhaust and Chip with egt probe