2001 Chevy Blazer Shakes at 75mph

Shakes or Wobbles problem
2001 Chevy Blazer 6 cyl Two Wheel Drive Automatic 75k miles

I cant tell if it's a tire problem or something deeper. My Blzr shakes mainly at 75mph. I feel a slight rocking when stopping from 5mph at a slow speed. The front tires are new, the back are fairly new. Rotors have been turned. 2 new shocks. A couple tie-rod pcs replaced. At 75mph, I feel it in drive, neutral and with the engine off. Feel it more in rear now. Maybe felt it more in the front before tire rotation. Cant really be sure though. I've gotten lots of suggestions but usually rules out by other advisors. Need to fix problem without going broke. Any ideas of where to start? Thanks for all your input!