For awhile now has been getting pretty low fuel milage

Fuel pressure checked out good. Have noticed a new clue. Scanner connected drive cycle monitor was showing egr/vvt inconclusive think that test is being canceled because of a issue I have just discovered. While driving when I let off accelerator for a few seconds it goes out of closed loop. Into open and back into closed loop at idle when raised say 2000 rpm and released does same thing so I believe is cancelling egr mon test. During this quest at one point when I let off accelerator going down hill would down shift up shift as if was changing in and out of overdrive so I suspected throttle position sensor first I put another one on it from a parts car I have and still no change then I put original one back on and no change light finally came on said tps open condition below threshold realized adjustment was below threshold adjusted to specification the light stayed off the up and down shifting stopped but poor fuel econ persisted egr still inc and as stated before still dropping out of closed loop on deceleration both o2 have been replaced. Have cleaned intake and completely flushed egr passages both directions ect does have a slight stumble at idle Maybe this will help draw a picture of the issues I am scratching my head about. Thanks for your time