Sparkplug replacement in 3.3L Engine

I need to replace the sparkplugs in my 98 Grand Voyager (3.3L engine). The back ones seem to be impossible to get. Can anyone tell my how to do it?
I appreciate any help.

You are right this is a very difficult replacement. If you have a lift you can reach up between the firewall and the back of the engine and have good access to the plugs. If you do not you will need to remove the plenum from the intake manifold and do the change from the front of the van. I had a t&c with the same engine. Took it to a shop and had it done. Well worth the price!