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missfire = cracked spark plug

6K views 12 replies 9 participants last post by  schuedog 
#1 ·
So my 08 G6 GT 3.5L started with a slight missfire at idle and low rpm acceleration. So I took it to the dealer and after performing some tests the checked the plugs and found a cracked spark plug, it was cracked and the top and went almost half way down the porcelian. So the dealer replaced the plug and put new wires on the car as well.

Just seeing if anyone else has had this issue? The missfire became more pronounced in damp weather.
 
#5 ·
I can't imagine a spark plug "just cracking" unless there's an unseen problem.
Has your 6 overheated, have you sprayed the engine bay w/ water, have you had any other work done under the hood that others/yourself would have bumped a plug?
 
#6 ·
First time was a the cyl 1 spark plug, this time was the cyl 5 spark plug. also none of the above has happened. I am just wondering if it was a bad batch of plugs? I am going to replace all the plugs after the holidays unless there are other issues with the car.
 
#8 · (Edited)
Done with GM!! Due to My latest G6



I have an 08 G6 HTC with the 3.9 liter. 42000 miles and number 1 cracked, 200 miles later Number 1 cracked again. I installed them myself, there where no defects to the plugs and I did not drop nor over tighten them. Seems like another GM issue that they do not want to address nor do anything about. I swore I would never buy foreign but I just bought my daughter a Mitsubishi that was assembled in the US instead of buying my TENTH GM product. And they wonder why they can not keep customer loyalty!!:(


UPDATE. My wife will not let me sell this crap!!! 46998 miles and the darn plug is cracked again!! Not a problem with the engine you say?? Well the odds are against you gm. The problem is not a bad batch of plugs, they are not from the same store and bought at diff. times, so therefore it has to be caused by an issue with the engine, and if you look at the posts all over the web it is not just my engine. Buying myself a new van and it will NOT be a gm product in any version!!!!!!!!!!!!!!!!
 
#13 ·
Not just this.



Every G6 with the 3.9 that I have driven with over 30000 miles sounds like an old beetle, it is the resonator, GM denies any problem and will not fix ($70.00 aftermarket will repair and not come back unlike the GM $500.00), the trunk weather stripping was torn at the top of the trunk by the windshield (the trunk lid head liner was not cut properly and clearly could be seen ripping the weather strip when I took it in for service) again not GMs problem they just make the cars. Now I search for miss fire issues and they are all over the internet and most of them with the #1 cylinder and again GM wants to charge over $500.00 for plugs and wires. So in answer to your question and knowing a lot about cars and how they work I say YES it is all GMs fault. They do not want to fess up to any mistakes. Oh and did you see that this is not the first GM that I have owned??
 
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