Generation III Internal Engine 1997-2006 LS1 | LS6
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Old Feb 9, 2006 | 11:03 AM
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Im getting a misfire from cylinder 7, its not ignition, i changed the wire and plug. I believe its valve train because im getting a loud ticking from that cylinder. Whats funny is when i give it good gas it still performace the same. I even had some buddy of mine come check it out and they all say its the valve, what could be the problem with it? any help is appreciated, thanks
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Old Feb 9, 2006 | 11:08 AM
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Bent pushrod is the most likely culprit. Have you done a compression test on that cylinder? That's what you should do first. Then if it shows a compression problem, pull the valve cover and remove that pushrod and check for straightness.
If it's straight you need to pull the head.

If there is no compression problem at all, then you might need to reconsider the source of your loud ticking, and swap the coil for that cylinder with another cylinder.

Just because the power feels the same, doesn't mean anything. You can easily lose 10% of the power and not really be able to tell.
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Old Feb 9, 2006 | 11:29 AM
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Originally Posted by jyeager
Bent pushrod is the most likely culprit. Have you done a compression test on that cylinder? That's what you should do first. Then if it shows a compression problem, pull the valve cover and remove that pushrod and check for straightness.
If it's straight you need to pull the head.

If there is no compression problem at all, then you might need to reconsider the source of your loud ticking, and swap the coil for that cylinder with another cylinder.

Just because the power feels the same, doesn't mean anything. You can easily lose 10% of the power and not really be able to tell.
I havent done a compression test yet but im planning to. Do you think it could be the coil, a bad coil wouldn't cause a ticking sound would it?
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Old Feb 9, 2006 | 11:39 AM
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A coil will make a ticking sound if it's arcing to ground.

Try swapping coils between cylinders and see if it follows the coil.
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Old Feb 9, 2006 | 11:59 AM
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And the ticking sounds could be something else. Ticking sounds are normal...air system check valve, lifter bleed down (valve clatter), piston slap...

I'm not saying you should ignore the possible implications of the sound, just don't use the ticking sound as your only consideration in making a diagnosis.
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Old Feb 9, 2006 | 12:31 PM
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If the coil pack is bad would it cause a loud tapping sound? it seems like it gets louder as the car gets warmer.
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