95 Escort Wagon Vibration above 60 MPH?

I have a 95 -1.9L- Station Wagon 127000 miles on it, in Very Good Shape. Mostly freeway driving. I am getting very bad vibrations when I press on the gas when I'm doing anything above 60 MPH. If I put the car in Neutral going down an overpass or bridge the vibration goes away even up to 70 MPH. As soon as I put it in drive an give it gas, the vibration starts again. Going up hill with the peddle to the floor (high bridge) the inner door panels want to shake off! I am getting illregular tire wear on the Left Rear. Even after rotation.
I have done the following to no avail:1) Rotated & Balanced the Michilien Tires twice. 2) 4 wheel alignment twice, 3) inspected the monroe gas shocks and struts, OK. 4) Balanced tires again. 5) Tuned up the engine. 6) Had all 4 wheel bearings checked. even the ones on the drive axles, Sealed units on the rear. All OK.
All this started after I had the timming belt brake on me and then replaced. The valves were checked and found no damage. The car has very good accelaration, and runs very well except for the vibrations. Could this be from something done during the timing belt change out? If So what? Does this 1.9L have balance shafts in it as some other makes do?