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Discussion Starter #1
I am going to attempt to change my spark plugs and wires on my 99 Seville this weekend but I first wanted to know if it was a big job. What tools are best used (Indexible socket wrench and u-joint socket)?

Is it a pretty easy job?
 

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'87 Jeep, '10 Thruxton, '00 Duc 748, '01 748R (853cc)
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Re: Changing Spark Plugs- '99 Seville STS

Yeah, it's a pretty easy job as long as you have the right tools. You'll need a metric socket set to remove the ingition module (with packs still attached). You'll also need a 6" extension and spark plug socket. I recommend running the new wires through the old looms before you put them in,s ince it can get kind of confusing. Try to change on at a time. New wires aren't numbered either, so you'll have to match them up by length to the old ones. Use a small Sharpie marker to number them once you've figred out which one is which. It's about a 1.5-2 hour job depending on how experienced you are.
 

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2005 STS4 1SG: GM Acc Lights, Corsa, Platnium Grille, Volant
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Re: Changing Spark Plugs- '99 Seville STS

make sure you replace them with platnum plugs or else!!!
 

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White Diamond '03 DHS (with DTS floor shift)
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Re: Changing Spark Plugs- '99 Seville STS

Be advised, ther are 2 hidden bolts on the backside of the ICM that require the Braile method to R & R.
 

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Discussion Starter #5
Re: Changing Spark Plugs- '99 Seville STS

CadillacETC1997 said:
make sure you replace them with platnum plugs or else!!!

Can I get these Platinum plugs at Autozone?
I also need new wires....what type should I get?

Ranger, you mentioned 2 more bolts to remove but in my service manual it doesn't mention anything about this, does this also pertain to my 1999 STS and if so can you go into detail about it a little more? Thanks
 

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White Diamond '03 DHS (with DTS floor shift)
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Re: Changing Spark Plugs- '99 Seville STS

clusco said:
Ranger, you mentioned 2 more bolts to remove but in my service manual it doesn't mention anything about this, does this also pertain to my 1999 STS and if so can you go into detail about it a little more? Thanks
Well, I can't vouch for the '99 but, I suspect it is the same as my previous '97. Remove the obvious mounting bolts on the left and right side of the ICM. If it then lifts off, your in buisness. Mine would not come off. Upon further inspection I found two more mounting bolts on the back side (firewall side). As I mentioned, they were impossible to see. I had to get at them by feel, which made it a bit of a PITA. My daughter has a '99 and is supposed to be over a little later. I'll check hers and post back.
 

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Re: Changing Spark Plugs- '99 Seville STS

My 99 STS has the 2 rear hidden 10mm bolts on the ICM and the one on the passenger side has a ground wire under it.
 
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