Not to shame you more, but when I interneted those plugs they came up as platinums.

It's not a good idea to run platinums on a 3800. We have a waste spark ignition systems and they cannot handle it. WSI will fire the coil for 2 cylinders on every compression stroke, be it intake or exhaust for whatever cylinder and plats break down quickly and dont hold up.

Some may last a few thousand miles or they last 10 minutes before they die.