Rep Power: 0

My 01' Civic has some issues in the front end. When in 5th gear going over 50 mph the car will begin to shake (left to right) almost as if the right passenger side tire were wobbling. When braking at speeds of 40 mph or more the car will also do the shaking/wobbling but the braking will be rhythmic (again as if the tire itself is wobbling). The pads are about 4 months old. The rotors are original and the entire front end suspension was replaced by Honda about 3 years ago. I am trying to get an idea of what the issue is. The car has 230k on it and generally runs well but is starting to show its wear mechanically. It seems it is burning oil as well and the trouble code P0420 comes up when scanned. I haven't replaced the ob2 sensor or the cat, but the engine seems to run fine. Anyone have some imput as to what may resolve the shaking up front?

 
Rep Power: 234

For the P0420 you need to replace the catalytic converter if you've already replaced the sensor(s).

For the shaking: Lift the front of the vehicle and shake the wheel in and out. Top and bottom movement is a bad wheel bearing and front and rear movement is a bad tie-rod.

 
Rep Power: 0

Sounds like your wheels could be out of balance, especially if this happens at higher speeds.