Join Date: Apr 2003
Location: Waipahu, Hawaii
Well, if you haven't changed the plugs in a while you won't be burning fuel as efficiently. If the plugs are in bad shape it could effect your gas mileage and power quite a bit. The 3.3L engine is really easy to do. I'm not sure about the 3.5L but since both engines are mounted longitudinally it shouldn't be that hard. All you'll need is a socket wrench, an extension, and a universal joint if you've got one.
By the way, avoid platinum plugs. I've seen first hand that these cars don't take very well to them... although the 3.3 seems to run okay on AutoLite platinums.