1993 Chrysler Lebaron shakes when in idle

Hi everyone I have a 1993 Chrysler Lebaron shakes when it idles I can feel shaking in the steering wheel when its idling. However when I am driving around I dont feel the shaking. Could this be a bad spark plug that needs replacing? I put some fuel injector cleaner in the gas and it seemed to help a little bit.
On a side note my brakes are squeeking when I am stopping. Do I need new brakes?

Perhaps Polygon could chime in here... he has tons of K car experience. To tell you the truth, I've never been in one that didn't shake rather violently. The engines are not notably smooth and it seems that a certain RPM seems to make them shake.

Perhaps Polygon could chime in here... he has tons of K car experience. To tell you the truth, I've never been in one that didn't shake rather violently. The engines are not notably smooth and it seems that a certain RPM seems to make them shake.

dealer fix, special weight needs to be installed inside steering wheel. Not uncommon for these cars