1997 Mercury Tracer vibration

Have vibration in steering wheel starting at around 70 mph on the highway:
-This started after changing out front braked pads, but the brakes are smooth when applied with no vibration also turned rotors by hand to check for any grabbing on pad everything is fine.
-Jacked up car and checked for wheel movement, everything seems tight.
-Swapped tires around to see if a tire was out of balance.
These are some of the things I have tried.

Are you torquing the wheels in the proper pattern and to the proper spec? I would assume that since the tires were rotated and the problem did not move, they are not out of balance. Warped rotors usually pulse when the brakes are applied. Was there any rust behind or on the rotors that could keep them or the tires from seating flush?