Well first off you shouldn't use either of those plugs, use the Autolite DoublePlats or the Ford Motorcraft double plats.
Changing the rear plugs is a *****, two ways.
1. Lots of swivles and extentions and do it blind. or
2. remove the UIM, and do it partially blind..
and while the UIM is off, you can clean it.
Changing the rear plugs is a *****, two ways.
1. Lots of swivles and extentions and do it blind. or
2. remove the UIM, and do it partially blind..