Need help

Hey everyone,

Just got done changing the water pump in my ride. Talk about a PITA. Well after that I just figured I'm going start tinkering with this ride & doing some mods. Anyway, I have a 2001 4 door but not sure of the model, here's my problem. When I come to stop light & in idle, the car starts to vibrate real rough & if I have the a/c on it just gets worse. Now if I put it in neutral if stops. The motor mounts seem to be in good order. I've heard of an Idle Air Sensor but not quite sure of what it is or where it's located. This had happened before & I had to replace a broken hose that was about 2" in length of the front of the motor. Didn't know what it did or nothing but as soon as I replaced it, the motor ran fine. I had hoped it was the same thing this time around but no luck. Any help would be greatly appreciated & sorry about the long post.