Random missfires can be caused by several things.yes plugs is usually the first thing people think is the cause,however,bad or dirty injectors,sticking valves,poor fuel pressure,dirty fuel filter and several other things.since you have replaced plugs,i am assuming you gapped the plugs to specs,i would check fuel pressure and if you have not changed the fuel filter for a while i would change it.since its a saturn they are known for the valve system getting dirty and causing the valves to stick in the guides.have the fuel induction system cleaned as this will usually clean the valve system and stop the valves from sticking.have this done at a shop that can perform this type of work as the chemical that you buy at a parts store is not the same.just somethings to check out.