[ironman1916]

Hey everyone my name is Dave. Have gotten a lot of great information off of this site since I bought my 04 cts last year.Southern car, no rust. Car was in storage for winter, (I am in upstate NY, road salt sucks), and I want to change plugs before getting it back on the road. Thought a brief introduction was in order, this is my first post. I have been working on cars for 30 years, and have a solid mechanical/electrical backround.

Here is my question. I have watched u-tube videos and have seen information here on this site for plug change that informs me to loosen the plenum enough to get the plugs out, and gives detailed instructions on how to get the plenum loose enough to do this. How much more difficult is it just to remove the plenum? Think this would make life a lot easier, and would allow me to inspect any plenum gaskets. The thought of cracking the plenum loose, and just hope it re-seals again scares me. Car has 100k miles. It was a corporate car, some suit used it for road trips. Car is perfect and well maintained, and engine still runs strong, lots of power. Little misfire maybe at the end of last summer, that's why I want to change the plugs. Even a re-useable gasket after 100 k miles may have damage, or debris around the gasket could mess up the seal.

Also used to work for ACDelco. ACDelco plugs recommended here???

Any input is appreciated. Thanks!!!!

 

[deyobr]

I've done the spark plugs and the coiils and one injector. All required removing the plenum and I went ahead and removed it entirely both times. Last time I did it fof the injector, it took me about 3 hr. and that included a trip to the store to buy the injector.

It's not too hard once you get everything disconnected and the very back bolt out. I would suggest removing the left (passenger) windshield molding. There is a "box" with two nuts and one bolt that you can remove. Once you remove it, the molding comes off. That enables you to get a ratchet in to get that last intake bolt out. Otherwise you have to do it with some really messy wrench work.

The last bit that is a little challenging is the front bracket. Loosen the big bolt holding it on, remove the bolt that attaches to the intake and rotate it clockwise out of the way. The intake should lift right off.

 

[mattt0305]

Easier than taking that molding off is just buy a little tool that snaps into a socket that let's you use a wrench on a socket. Sears sells a little set of 3, one for 1/4, 3/8, and 1/2 inch drives each. Like thishttp://www.amazon.com/Piece-Square-Drive-Socket-Caps/dp/B00O3A7GVE

 

[grill master d]

Very easy...i was scared the first time....had mine off 4-5 times.....same gasket>today has 148k mi ...

 

[Kingoftypos]

Very easy...i was scared the first time....had mine off 4-5 times.....same gasket>today has 148k mi ...

I second that. And I didn't read any instructions when I did mine.

Though that passenger side rear bolt is a major PIA! There have been some tricks here and there. Some, like me, have used some duck tape to hold the bolt up while you removed the intake. While others have removed the plastic piece that is blocking it from being removed. From what I understand, you'll have to remove the battery for that.

KOT

 

[CTSM]

At 100K miles? I would definitely consider not only removing the plenum and changing the plenum gasket and plugs I highly recommend replacing the original ignition coils with better quality ignition coils with a lifetime warranty.

All my original ignition coils failed way before 70K miles.

Coils are expensive, while 3 of the 6 were replaced under warranty I replaced all the leftover coils with Borg Warner (BWD) coils because they were good quality and have a lifetime warranty, versus the AC-Delco coils which only have a 1 year warranty.

Not only that, the AC-Delco ignition coils were almost a $80 to $100 and special order in certain stores, while the Borg-Warner BWD ignition coils were $65 it's a no-brainer choice, if AC Delco did good enough quality control they wouldn't have all failed like that before reaching a 100K.

I have no ignition coil related problems since replacing my original coils.

As for spark plugs, while I was there I replaced all my original ones with Denso ITV16 Iridium #5338, 40K miles later thank God no misfires or lowered performance.