03 Edge 2wd manual trans 16" stock size wheels and tires...

This has been going on for quite some time....and I'm ready to investigate...
It drives out really nice on a smooth road.....but on the highway...at about 65...on a less than perfect road....I get slight shimmy in the steering wheel.

It.s done the same thing with 3 different sets of wheels and tires...so we are assuming that is not the problem..

I've done the usual tugging on the wheel when raised and haven't seen any thing sloppy or loose.

Any input before I take it to a shop?