How to replace the back three spark plugs

Have you tried getting your arm and hand back there? If you can reach the spark plug boot, you got it made. Twist and pull to remove spark plug boot. Use a spark plug socket and rachet, proper extensions, maybe a breakover, maybe a universal joint. whatever it takes.

Some people rock the engine forward to get at rear spark plugs. Some makes and models, it might be easier to get at the sparkplugs from underneath. Whatever is easiest for you, thats a judgement call.

Unbolt the front 2 motor mounts and use a ratchet strap there is a spot towards the rear passenger side of the engine to place the hook on one end of ratchet strap, then find a secure place to hook the other end of ratchet strap, then pull slack out of the strap then ratchet it and you will see the engine come forward exposing enough room to get your hands in behind the engine to change plugs, or can reach from under the vehicle, the venture's and the lumina's both have to have this procedure done in order to change the plugs, Lumina's are much easier though. Good luck hope this helped.