What would cause the 6 cylinder to misfire in a 3l That is in a 1998 caravan?

I just changed my plugs and wires today. The Service Engine Soon light is off. I am not a mechanic and honestly, I don't think you have to be one. It is not complicated, but it is difficult. I did go ahead and change my ignition rotor and distributor cap. I am glad I gave this a shot, but I probably wouldn't try it again. It is now vibrating quite a bit and I need to figure this one out. I hope this helps you...