It’s amazing that no one has solved the old violent steering wheel shake on the classic mustang and cougars. I have one that didn’t have this problem for 18 years then developed it. I commenced to rebuild the entire front end of the car. And the problem is still there. As long as I drive straight and don’t hit any bad bumps it’s good. But any turn of the wheel or big bump in the road and. It goes out of control. I literely have to slam on the brakes before having an accident. Everything has been replaced. NO improvement. I an ASE. Master auto tech and this one has me stumped. I keep wanting to blame he ole power steering setup but it’s been replaced. Anyone got a clue. It’s totally unsafe to drive..