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Discussion Starter #1
A few months ago I bought a 2004 Cadillac CTS with 30,000 miles on it

Recently I got a P0303 which is a cylinder 3 misfire.So i'm going to take everything apart till i can pull the plug and check the coil on plug. I guess you can check the resistance with a multi meter and see if it works, If i'm not confident with that I'll swap it to another cylinder and see if the misfire changes cylinders. I had some other code that said multiple misfire but i don't remember what that was.

Is there any other way to test a coil on plug? Anyone know the resistance it's supposed to show?

also I've had several fords. It was easy enough to find factory parts because they're all labeled motorcraft. Motorcraft was better than a lot of aftermarket parts like motormounts and O2 sensors. They either wouldn't work or wouldn't last. Does anyone know what to look for when seeking factory parts? maybe GM has a specific Brand name.

and last question, does anyone know of a good place to find factory parts? some ford forums had ford parts dealers on their forums that would give good prices on ford parts.

thanks for any input
 

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2007 CTS 3.6 >128k miles
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I can answer one of your questions. GM uses ACDelco for most things including spark plugs and many other electrical items. However, as I was replacing one of my coils with a new ACDelco D501C i noticed that the original was Bosch 0221604112. I then checked further and both of these are listed as OEM for my 2007 3.6L. I would therefore get the Bosch if I were doing it over, just because it is cheaper at Advance Auto (order online and use code: COUPON25 to get 25% off). Besides, the ACDelco unit is probably just a rebranded Bosch.

Also, Advance is the best price I have found on the correct ACDelco 41-988 spark plugs when you use the 25% off code. Other parts are usually cheapest at RockAuto.com but ya gotta have a big enough order to be worth the shipping costs.
 

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2019 Silverado LD | Blacked Out
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Coils are usually the culprit. Shoot me an email I can help you out with any diag questions and quote you up anything you may need.
 

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2004 CTS 3.2, 5-speed
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Dehacked - my '04 CTS 3.2 miss turned out to be caused by leaking valve cover gasket that filled up the spark plug well with engine oil. When I replaced the VC gasket I also replaced the coils as well since I was already that deep into the teardown. Coils were reasonably priced at Rock Auto.

Good luck.
 

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Discussion Starter #6
wow thats a random problem. I haven't seen that one before, I'm gonna start with the spark plugs go from there
 

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Discussion Starter #7
Looking at the coil I'm not sure if its a random set of numbers or an actual date. but it says 04-01-14. If it is a date this concerns me since the car only has 30k miles on it.

Anyone know? I don't know why it seems to be hard to find torque specs for plugs and upper plenem bolts
 

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2007 CTS 3.6 >128k miles
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Haynes lists the torque for spark plugs at 15 lb ft and the intake plenum bolts are 89 inch pounds in sequence.

However, the factory service manual states 17 lb ft. for the plenum bolts starting in center and going in circular pattern outward (I used a cross pattern for the four long bolts first, and then did the front and back short bolts). This video (below) by 1A Auto also states that the plenum bolts should be 17 lb ft.
 

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Discussion Starter #9
oh cool thx for the info. Yea 89 inch pounds seems a little light. It's hard to know which is right when there are different numbers from different places. I bought a bootleg factory service manual on ebay and it didn't even have the section for replacing sparkplugs so i got a refund
 

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I also noticed several other incorrect torque numbers in the Haynes manual (vs the FSM) when I did my chains so I am hesitant to rely on their numbers. At least 15 lb ft for the plugs is consistent between sources!
 
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