We'll I just did a tune-up on my 2004 pacifica 3.5 Liter. It wasn't too much of a hassle, but you do need to take off the upper manifold, in order to locate the plugs... First you take off the sexy plastic cover that says "chrysler 3.5 liter 24 valve". No you will see the upper manifold. Its seven long 10mm screws on the top half of the manifold... And several small screws around the sides... Don't forget the screw connecting the oil dipstick to the manifold. Once you remove the upper manifold you will see the 3 coils which house the spark plugs underneath them... You will need a really deep 16mm socket to get the plugs out.. The only socket that I could find to do the job was one with a 1/2" drive but whatever works... Have fun be careful and drive safe... Remember the plugs for this vehicle is gauranteed for 75,000 miles so if you aren't at 75,000 yet then you needn't worry about replacing the plugs at all. But if you are over 75,000 and are replacing I wouldn't change them again til I reach another 50'000. I hope I was able to help
