[Xmann01]

Wow, thats a pretty thorough explanation of the problem.

When I usually get a car with a problem they just tell me..... its broken, fix it.

Hmm... Try putting it in neutral while coasting at that speed to see if it still does it or not. It's an odd problem no doubt. I'd make a note of the RPM's at the speed of the problem and take it to that rpm range in neutral or at a higher speed at that rpm. I'm sure the other guys will jump in and give their ideas. Hope this helps!

EDIT: Also...... perhaps the egr is opening at 35mph and getting stuck open, open too much, isnt supposed to open (yet)? Hmm...