What might be causing this? It starts around 35-45 mph, goes away when I give it a little gas ot take my foot off the gas pedal. Feels like I am driving on ruts. Pretty persistent. I have new tires, recently had front tie rod replaced and new brakes. Help?
This sensation can be caused from what is called wheel hop. This when struts/shocks lose their dampening effect to keep the tires on the road. This then allows the tire to start to hop up and down off the road when it reaches a certain speed or frequency. and it can feel like driving over a washboard surface.
Just find a safe place where you can drive the vehicle where this condition occurs, and with someone in another vehicle following, when it happens, give them the thumbs up, then have them check if any of the tires are bouncing up and down on the road surface.
So you have an automatic transmission or manual?
And what might I do if they are bouncing up and down? Would this mean new struts? I have been told they are very expensive. My car has about 160,000 miles on it.