Tools required:

• ratchet with 10mm, 12mm, & 14mm sockets
• spark plug socket (17mm??)
• 3" & 9" extensions for ratchet
• pliers - one regular and one needle nose
• jewelers flathead screwdriver
• can of compressed air or air hose (optional)
• can of carburetor cleaner
• clean rags and newspaper
• one quart size plastic bottle like motor oil or a sturdy piece of wood or simular about that height used to prop up the air intake plenum
• security code (if you have stock radio)
• one tiewrap if you have to cut the one under air intake hose (optional)

Replacement items:

• Denso Iridium Spark Plugs (IK20, qty 6) picture
• Magnecor Spark Plug Wires (KV-85, qty 6) picture

Removal of air intake plenum:
First of all, the task at hand is really easier than it appears. The only thing is... it takes time. If you know nothing about cars or what things are under the hood, I suggest you take a look at figure 18 and see if this is comprehendible to you. If it is and you have the tools and feel comfortable, please proceed. If not, I suggest you find a qualified mechanic instead of doing it yourself. The plenum itself is actually very easy to unbolt, only 13 bolts & nuts hold it in place. (fig. 19) What makes it complicated is all the other stuff you have to unbolt and move out of the way so your plenum is free to completely flip up and give you full access to the sparkplugs.

To make things easier, after you unbolt the item and move it out of the way, always put the bolts back into that socket when you can. This way, there is less bolts to remember where they should go. For the other bolts that you have to remove, place them on an unfolded newspaper relative to the position of the plenum. Just picture the center of the newspaper as your plenum and place the bolts onto the newspaper in the same relative position to help you remember where they go later.

Let me give you some general information first so you will get a better picture of what we are attempting to do and what it is that we are moving out of the way for our ultimate task. Yes we are attempting to move the plenum out of the way, but there are some things that are attached to the plenum we really don't have to worry about. (fig. 6 & 7) These things will stay connected and moved together with the plenum as one piece. They are the throttle body, throttle cable adjustment bracket, all EGR vacuum hoses and valves. I will be referring to the 22 pictures below throughout the instructions. 

If the 22 pictures is still not enough, I have an additional page with even more pictures for your reference. Just click here! Yeah, you can say I went a little overboard but I wanted you to have all you need to do this. Actually, that was my first attempt at documenting it but it wasn't clear so I redid the whole thing just for you below =)

Ok, let's get to work.

1. Battery
Disconnect the negative cable of your battery. Just remember your security code if you have stock headunit (radio) and also remember your favorite radio stations. 

2. Air intake hose
Loosen hose clamps of air intake hose by the MAS on one end and the by the throttle body on the other. (fig. 7 & 8) Remove vacuum hose on top of intake hose and unhook strap underneath the intake hose. This strap holds up two fuel hoses under it. If it's tight, you can loosen it or cut it and put another tiewrap back on later. I was able to open the latch on the tiewrap to loosen it. Wiggle free air intake hose and remove. (fig. 12) I suggest you clean your throttle body at this time with a clean rag and a little carburetor cleaner. Mine was really filthy. 

3. Plenum
We'll unbolt the plenum next. Start in the back of the plenum by the firewall. Take off the four 12mm bolts on the left side. (fig. 1, 5, & 19) When you do the two bolts for the EGR pipe, be careful not to loose the gasket. (fig. 2) There is one more 12mm bolt on the right side in the back. It's about in between the plenum and the throttle body. (fig. 19) Next, go to the front and unbolt the five 12mm bolts, the two 12mm nuts (one on each side), and the 14mm bolt on the bottom left. Make sure you take out and save the two washers under the nuts. A needle nose pliers helps to get the washers out (be careful not to drop them). Place all bolts and washers on your newspaper accordingly. 

4. Washer bottle
Lift washer bottle straight up and move out of the way. Now you should see another 14mm bolt. Loosen this bolt that is connected to the rod where you removed your other 14mm bolt and swing rod down and clear of your plenum. (fig. 13 & 17) 

5. Throttle cable & wire rail over fuel injectors
Remove the two bolts holding the throttle cable to the front of the plenum and the four 10mm bolts that are holding down the wire rail that is over the injectors. (fig. 14, 15, & 22) Move throttle cable and rail out of the way of the plenum and place bolts back on plenum. Place the two bolts from the far bottom right on your newspaper accordingly (on the bottom right, duh). 

6. Left side of plenum
Remove bolt on bottom left of plenum. (fig. 13 & 14) Move wire harnesses out of the way and put bolt back on plenum. There are also two wire harnesses you have to unplug. One is black and the other one further back is brown. Squeeze the back of the harness to release it. 

7. Right side of plenum
Remove bolt for grounding straps and sensor and unplug the vacuum hose that goes to the fuel pressure regulator. (fig. 16) Going just a little further back, you will see another bolt on the side that holds a wire harness. (fig. 15) Remove this bolt. Move everything out of way and put bolts back on plenum. 

8. Wire harness & wire holders
Removing the wire harnesses requires you to unclip a metal wire that holds it in place. To do this, you have to use your a very small flathead screwdriver like a jewelers screwdriver and pry up the wire on each side while pulling at the connector. I prefer to do it this way because I don't have to worry about damaging the sensor. Just be careful here and take your time. (fig. 6, 10, & 11) There are also two plastic clips that hold the wire loom in place. One leads to the sensor on top of the plenum you just unclipped the wire harness for (fig. 10), and the other is down on the side between the vacuum actuator and the throttle body. (fig. 11) Use your super small flathead screw driver again and press the back of the plastic legs that flair out so you can pull these out of their mount. Once all are unplugged or unclipped, move wires out of way. 

9. Throttle body hoses
There are two hoses that must be removed from the throttle body. Both are under the throttle body; one is in front and the other is in back by the firewall. We will be looking at it from the right side. (fig. 3 & 4) You can either pinch the hose clamp with your pliers and slide the hose clamp down the hose first then pull the hose off or pull at the hose at the same time while you pinch the clamp open. I prefer the latter as there wasn't any room to really move. It helps a little to twist the hose and clamp together a while pulling outward. Don't worry if you have a little water coming out of the hoses. 

10. Lifting plenum
The plenum should be free to lift up now. This shouldn't really take any force. I know I didn't have to pry at the plenum at all. Just lifted at all four corners until it was loose then lifted straight up until it was free of the two bolts in the front (remember the two nuts you removed). Now do NOT pull it all the way back yet. Just prop it up about four inches. There are still a couple of things you need to do first before you prop it higher than this. 

11. Unlatch wire
Ok, we have to go back to the left side one more time. In the back, there is one wire that runs from under the top left side of the plenum over to the area where all your belts are. (fig. 9 & 10) It's the only wire but you have to free this wire to give you slack to pull the plenum all the way back. It is held by two rubberized metal wires. 

12. Wide Open
Put a rag on the back by the firewall on top of the heat shield for the exhaust pipes. This is to keep the back of the plenum from scratching the heat shield when you lift the plenum up. Now prop the plenum up the rest of the way by positioning your bottle of motor oil or a piece of wood under the plenum and on the valve cover in the back (the black valve cover) behind the three spark plugs. Look at the gasket for the plenum and notice the tab on the bottom right. (fig. 21) Be careful removing the gasket if you plan on reusing it and wipe off any oil on it. Wipe off any oil you see on the plenum and use your carburetor cleaner to hose off the oil in the plenum. Make sure you clean the part that touches the gasket (both sides) really good. Make sure you also cover the fuel injectors with rags or newspaper so you don't drip carburetor cleaner all over it. Next clean off the valve cover in the back. 

13. Replacing spark plugs & wires
I suggest you unplug all your spark plugs but do NOT remove your wires yet and definitely do NOT unplug it from the distributor cap yet. Just leave them all lying there on the valve cover. You should replace one wire at a time. Replace all the spark plugs at this time using your spark plug socket and 9" extension. This is also a good time to inspect your old plugs to see if your engine is running too rich or too lean. After replacing all the spark plugs with new ones, take out one wire at a time completely out and finish replacing that one before removing the next one. FYI, the numbers of the spark plugs are printed on top of the distributor cap but is really hard to make out. And the firing order is 1-3-5 in the back from left to right and 2-4-6 in the front from left to right. In case you removed all your wires, you can still get it right if you can see the numbers on the distributor cap. The silicon on the wires are bigger than stock but will still fit in the plastic wire organizers because of the really soft silicon covering on the wires. Just press them slowly in. Furthermore, when you push the wires onto the spark plug, it will seem like the boot that goes over the spark plug is too tall. It is not and just isn't in all the way. When it is in all the way, the top of the boot should touch the valve cover. If it isn't, just use the base of one of your open hands and place flat on top of the wire boot. Then place your other hand over your first hand (like in the position of giving someone CPR). Now apply firm pressure directly downwards for a couple of seconds and you will feel it click in. When you lift your hands, you should now see the top of the boot snug against the valve cover. Once you do one correctly, you will know what it should look like when it's plugged in properly. Repeat this for all six wires and you're done. 

14. Putting it back together
When bolting back everything, just do everything in reverse order. Use your compressed air or air hose to blow clean all wire harnesses before connecting. Make sure you don't over tighten any bolts. To restrict yourself from doing that, hold the ratchet all the way to the top (opposite end from the handle) so you don't have any torque and tighten. The only bolts that are torqued a little higher are the 12mm & 14mm bolts. Everything else, low torque. The last thing you should do is reconnect the battery. 

15. Crank it up!
Now crank your car over and pat yourself on the back. Don't forget to input your security code on your stock headunit. How can you cruise without tunes! You've learned a valuable lesson because now you are no longer at the mercy of your dealer to change or inspect spark plugs or spark plug cables or any other time you need to get under the plenum =)  Now take that savings and put it into other things for your Galant!

If you use this little guide and find it useful, email me with your comments.
Email: tjc13@thegalantcenter.com

*Disclaimer: This guide is to be "used at your own risk". I, (TJC) take no responsibilities for errors, incorrect information, and make no representations or guarantees expressed or implied for any damages, mishaps, and/or pain and suffering that this may or will cause you.