Hello. I have a 1997 Chrysler LHS, and I am having a very weird problem. It was driving perfectly fine up until about 2 weeks ago. Then, it started vibrating quite a bit on the front end. It seems to happen at speeds of about 30-45(in-town driving.) It doesn't happen when driving on the interstate. We thought maybe the tires needed to be balanced so we took it to the tire shop today. They ended up replacing the two front tires saying they were really worn, and also balanced them. Well, the problem is still happening. It is a back and forth vibration the almost feels like there is a flat tire on the car. It will start, and several seconds later it will just stop. There is also kind of a knocking sound that seems to coincide with the vibration. I am desperate for an answer, but I can't afford to take it to a shop right now. Any advice?

 

Curious does it do it all the time and does it go away after awhile. If you speed up does it go away? I know i just baught a 300m and had a problem with a thumping after i let off the gas but that was just loose lugnuts. I am still having a sound in the right front but thats a hub and bearing. I would first think in your case how are the sway bar links or tie rod ends. If you can get under the car and look you might be able to see if they are bad. If you can get it up on a jack you can check a few of these issues

 

it might be the transmission... if it has the wrong fluid, the overdrive doesn't engage properly right away and the tranny starts to vibrate at those speeds... if u havent changed the fluid in a while, have it replaced and see if it goes away.. i think yours uses ATF+4

 

Before looking into costly repair, check your tires to make sure you don't have any abnormal wear on them.