I am working on an '03 Neon right now with the same problem. The compression on cylinder #1 is low; not sure why yet. I would check compression (or have a mechanic do it) before you replace any tune up parts. There are quick and simple ways to determine which cylinder is misfiring without replacing any parts and to determin whether it is the spark plug, plug wire, coil, fuel injector, or something internal (low compression).
Tuesday, September 11th, 2012 AT 3:14 PM