I agree with scottbigred, that the job is much easier with the fuel rails off,
no doubt. A year a go I made the big mistake of not putting in Motor Craft plugs, this is why I had to do the job over, but this time I used MC Plugs and while I was doing the plugs anyway, I knew I needed to replace the COP's.
6 of my COP's were originals with 142,000 miles on them. Anyway when I did it about a year ago, I did pull the fuel rails and everything was easier to get to for sure. I didn't want to this time because it takes a bit of work to do it, plus I didn't want to mess with the injector o-rings etc etc. That was my 1st time pulling COP's and changing plugs on my 5.4L V8, so it probably took me longer to pull the fuel rail and put it back on than it would a more experienced guy like scottbigred and alot of other members on this site.
Good luck which ever way you go.
Last edited by tjk_in_cny; 12-04-2008 at 08:36 AM.