+1 on this!! I have a '98 Lincoln Navigator; last two spark plugs/coils on each side are so far back under the cowl you can't even see them. When I needed plugs, I waited until a local dealer had a "loss leader" special and let them do it. Coils are starting to die (not unexpected at 270K) so my ground rule is that I will replace 1,2,5 and 6; my mechanic will do 3&4 or 7&8 as one on each side fails. End of rant!!!On Ford stupidity. Have one in the shop now for ignition plugs replacement. 5.4 3 valve POS. The coils were removed and plug ports flooded with PB Blaster and sat for 5 hours. 7 of 8 plugs broke off. This morning, I'm going in to remove the lower portion of the broken plugs. The rear of the engine will be the most difficult because of the placement of the engine. I will probably spend about 3 hours getting them removed and replaced.
Ford is the worst for building a vehicle for maintenance. It's like they are put together as if nothing will ever go wrong and reg scheduled maintenance is labor intensive.