here is alog of a 2015 2.7 eco all stock. fuel trims -28 and then misfires. seems to correct itself after it pegs af lean 20af. once it corrects it will idle and then start trimming negative until its -28 and then it will misfire again. it does this about a dozen times only after refueling and then it wont do it again. log attached. anyone have insight on this?