Where are the back three spark plugs located on a 1999 Pontiac Montana?

Answer 1

opposite the front 3 under the intake manfold, you will need to remove it to access them .

AnswerYou can actually access the plugs without removing the intake manifold.

Unbolt both front dogbone engine mounts and use a ratcheting strap, pull the engine forward as far as possible. Then remove the plastic trim that covers the wiper motor arms, and reeeeeach. You might find it's easier to remove the plug wires from underneath the vehicle. A ratchet with elbow and an extension(s) are highly recommended for getting to the plugs.

AnswerYou will also have a little more room once the engine is tilted, if you remove the coil pack. 2 screws on the front, 2 nuts on the back.

Also when reinstalling the coil pack, it easy to disconnect a hose to the manifold fuel vapor suction system. GM wisely located a solenoid or sensor on the coil support bracket. After a spark plug change, if you get check engine indication that codes a fuel vapor system failure, look from below the motor an make sure the hard plastic hose to the solenoid switch is in place. Takes 10 minutes of tracing pipes, hoses etc, visually to see the hose is loose or off. Working from the top of the engine to remove the coil assembly, I had no idea there were things attached to it. Be careful.

I removed back wires and plugs from underneath,,have skinny arms...will never do this again,we had a Caravan and a Windstar that was hard enough to work on,this is worse.