your fuel filter, sparkplug wires and spark plugs are NOT going to affect your emmisions as long as you get a clean spark and enough fuel
look elsewhere for your problems, such as changing your seals and checking your exhaust sytem for leaks and a bad cat, or your EGR system
look elsewhere for your problems, such as changing your seals and checking your exhaust sytem for leaks and a bad cat, or your EGR system