steering vibration at stop

I have a 1988 Mazda MX6 and was wondering if anyone else had experienced a lot of vibration when sitting at red lights. When the car is moving or I am in park or neutral the vibrations are not there, but when I am in drive and just sitting there the steering wheel vibrates and the whole care does too. Any ideas what it could be and what I should do to fix it?

Also, the power steering pump went out on me a few weeks ago and have been driving around with no power steering. I dont particularly mind the extra workout around corners, but I was wondering if anyone knew if this was bad for the car (steering column/tires/anything). Do you think the extra vibrations could somehow be from disconnecting the power steering/compressor belt?

Any help would be great... Thanks!