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2004 chevy trailblazer_ls
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Discussion Starter · #1 · (Edited)
I have searched and havent been able to find a solution. I have been dealing with a cyl 6 misfire that I have not been able to solve. A while back i changed spark plugs and the cyl 6 spark had a bit of rust but hadnt been misfiring at that point. This morning a felt ambitious and went under the hood. I noticed that after i removed the coil pack on 6 that the gasket had been dry rotted a little and it was not seated flush on the valve. I swapped coil packs and plugs with another cylinder thinking maybe the plug was stripped or the coil pack was bad, but the swapped set still wouldnt sit flush on cyl 6. Made sure it was seated correctly on the plug but no manner how i tried putting it on it would not seat right. But now that i swapped the coil pack the engine is running smoother but not perfect. Does anyone know why the coil may not be sitting right or is this a common problem that there is no fix for? Any suggestions would be helpful. Thanks.

*There is also some rust on the coil pack
 

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2004 chevy trailblazer_ls
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Hey. The coil pack gives a little push back, due to the "spring", when putting it onto the spark plug, but just make sure that you get the boot onto the spark plug. Also, look inside the coil and make sure that the spring in there is not messed up. You dont want to push the spark plug to go between the spring and the boot.
I have been trying to run down an issue with misfire but no check engine light. I have replaced everything, and when I mean everything, I mean, everything short of buying a new engine and transmission.
This week we put the car under a load and wouldnt you know it, the 4 crappy coils that I got from oreillys are bad. The two brand new delphi are good. The delphi are on #5 and #6. 1-4 are some cheap off brand. WORD TO THE WISE!! DO NOT BUY ANYTHING OTHER THAN DELPHI FOR REPLACEMENT PARTS!! I have learned the hard way more than once about going cheap or going for the part that I could buy right now.
My spark plugs have less than 5,000 miles on them and I got the ACDelco iridioms. We changed out the 4 bad/weak coil packs and put in new delphi that the mechanic had on hand and BAMMM!!! Like a new, sweet, little muffin again!! I have been fighting this issue for well over a year. I cant believe it was the coils. Blows my mind that the GM dealership has had it 2 times and never found what we found in a matter of minutes!! They wonder why so many more people are going toward D.I.Y. I am done with techs!! There are no more mechanics.
So my main worry with you is, you said that the coil wont slip on the spark plug right. I would pull that spark plug and see if its broken or bent. I hope it wasnt cross threaded into the slot. It is the hardest one to get to so I can see how it would of been done. I use a rubber hose to put it in, or I put a piece of rubber up in the socket so it will hold the spark plug and you should be able to get it in there right. If you feel any resistance, then back out and try again. If the threads are crossed, maybe you can get it back on track and in the right threads.
My other point is this, If you have one coil that is bad, then you prob. have others that are bad/weak or they are not too far behind the one that is failing. I got all delphi coils off of amazon for $60 each. http://www.amazon.com/gp/product/B000CGM5T6/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1
I look at coils like spark plugs. You change them as a set. So change out all 6 spark plugs and all 6 coils. The coils are hard to figure out if they are weak. We tried to sitting still, spark test and they all tested great but as soon as a load was put on the car, they started to fail instantly. I even tried the unplug test, but each time I unplugged one coil, the car would run worse. So thats the worst test in the world.

FOR THE RUST- Its not rust, it is the burnt oil that got into the well that the spark plug is in. Unless you have a pool of oil in there and are losing oil, it is normal. Mine at 80,000 miles were the same way. It is a solid "rust ring" around the bottom of the plug. I can take a pic if you want. I kept them and all my parts that I pull off to give to the next owner, if they want them and so I can prove that the work has been done. I did do a valve cover gasket and spark plug seals and intake seals and throttle body seals right after I did the spark plugs. The oil worried me, but I later found out that it is normal. Oh well, least its all new again.
 
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