Definately sounds like a spark plug wire or the plug itself. One of the cheaper routes to look at. But get it rectified soon, because if it is misfiring, that means fuel will be making its way to the CAT where it can cause major damage - cause the CAT to overheat and possibly collapse.

'95 Contour SE - MTX All stock...except for my Canadian Tire cup holder 270,000 kms (April 2004) GO BABY GO!