Ashpeck, you don't mention the mileage on your car. The spark plugs should be replaced at 100,000 miles, or four years. Driving around with worn plugs is a great way to over-tax the secondary side of the ignition system (wires and coils). With that being said, I replace lots of ignition wires for rough idle complaints and CEL's, on cars that have had timely maintenance. In short, make sure your maintenance items are up-to-date first.