u need a wrench or a spark plug socket and maybe an extension.......remove the spark plug wire n start unscrewing the spark plug.....when u install new spark plugs make sure it is gapped to proper specifications,......u can look on the sticker under the hood, install same way u took it off, real easy
on the 2005 and later Ford focuses they have coil over, there for- you have to unscrew the bolt holding the coil down, once that bolt is removed, you simply just pull the whole unit up and out, once out you remove the spark plug as u normally would probably with a 6" extension, and the appropriate spark plug socket. and just reverse the process, there quite easy to do.
How to change the spark plugs
Sell it !!!
It is moderately easy to change the spark plugs on a Liberty, although it is rather tricky because of the gap between the spark plugs.
There is a cover on top of the engine. Take that off and the spark plugs are right there.
Wires and plugs constitute a tune-up. DO NOT gap the plugs, it will ruin the platinum coating.
Spark plugs and wires
Have a look at ; www.carbasics.co.uk
Changing spark plugs is relatively easy. Disconnect the batter and spark plug cables, and remove the old spark plugs. Next replace the spark plugs with new ones, reconnect the spark plug cables and battery.
This is for the '05 Frontier, but should be what you're looking for. http://www.clubfrontier.org/forums/f23/how-change-spark-plugs-2005-gen-2-frontier-40507/
Disconnect the battery, remove the spark plug cables and boot, and remove the old spark plugs. Put in the new spark plugs, attach the cables and boots, and connect the battery.
usually every 100000
NGK platinum plugs