While your at it, yank the front plug on the drivers and pass side and see if they look new. If they do, yank number 4 and see if it looks new. Alot of shops will do a shoddy tune up and only do the plugs that are easy to get to. When u have the front 2 plugs out, look at the boots. If they look brown, flared out on the ends, or feel sticky you should change them. If u need new ones autozone had a full kit with 8 boots and springs. If i recall its duralast part number 90003. If you do.replace the boots, get a tube of dielectric grease like what was mentioned earlier, and put a glob on the end that goes on top of the plug, and smear some around the little sealing ring on the boost about an inch below where it pushes onto the coil. Also, if you are going to replace the springs, use a pair of gloves and yank them off the bottom of the coil. Check the terminal where thr spring pushes onto. If theres any green stuff or corrosion, get a small flathead screw driver and gently scrap it off to clean the metal. What i found makes it very easy to install the springs is take a 13mm 3/8 shallow socket, put the 13mm end over the end of the coil and insert the spring thru the end that your ratchet goes on. Push down and youll feel it grab onto the terminal. The socket prevents the spring from cocking sideways and assures that you can push it onto the coil far enough. If you dont replace them, make sure all the boots are good, and all the plugs are new as well as running some injector cleaner on your next fill up, and clean the maf sensor. Also make sure ur air filter is clean. If you do that your mileage should increase signifigantly.
Hope this helps,
Andy