Stumbling at cruise range ??

[Sam-Son]

It's probably your EGR. Or a vacuum leak.

Seriously though, what did your tune include? New wires? Resistance check on them? Check the plugs? Do you mean it starts to stutter while you're traveling down the road?

New fuel filter done with the tune? Post more info, please, it will help with diagnosis.

+1 need more info but a bad fuel filter will cause some slight hesitation

[Chowchilla Skunkwerks]

Tune included wires, plugs, fuel and K+N filters. Happens only on the highway, in that happy zone about 70/75mph. Will pull fine all the way thru the gears just at that cruise speed. Thanks for the imput.
Rob