Ford: egr problem on 96 Ford E150 van

This van has a stutter or stumble just as the egr comes on both at low
speed, lite throttle or power braking, lite throttle, no codes runs
fine otherwise. Disconnect egr, no problem, I am wondering if somepone
knows if this can be corrected with an updated recalibrated egr or
Ford reflashing the pcm to delay the egr opening, tough one, I know.
Any input appreciated.