What engine do you have?
Here are your instructions for replacing the spark plugs. It is a pretty good job on the V6.
You have to remove the upper intake manifold to get to the back spark plugs.
2.Remove the three nuts and the engine appearance cover
3.Disconnect the cables.
4.Disconnect the throttle position (TP) sensor and idle air control (IAC) electrical connectors
5.Disconnect the exhaust gas recirculation (EGR) valve vacuum hose and EGR tube nut
7.Disconnect the three vacuum hoses on the back of the intake manifold.
8.Disconnect the vapor management valve (VMV) vacuum hose
9.Disconnect the two electrical connectors attached to the left side of the upper intake manifold
10.Disconnect the power steering pressure (PSP) sensor electrical connector
11.Remove the bolt and position the transmission vent hose and bracket aside
Now you will have to remove the coil packs and the spark plugs will be under them.
Remove the ignition coil-on-plug.
Now when you reinstall the upper intake manifold torque the bolts in this sequence.