I HATE starting new threads, but....

LS4me

LS4me

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So I changed out my plugs today (for some reason my wife's '06 doesn't mind those stupid +4 plugs [longish story] but mine does?). I fired her up and I heard a knocking, like spark knock, sound. There was no miss at all and the noise lasted all of 2 seconds. I chalked it up to the loose tools by the headlight as it ran smooth as silk. I tried it once more before cleaning up and it fired right up and ran like butter. After my and my tool's clean up I went out to give it a proper 'round the block test drive. Now I have a miss that triggered the CEL. The miss stops and the CEL is steady, not flashing. I run the code; miss cylinder 8. As the car runs like butter I clear the code and do my test drive. No miss and the car runs great.

Now, what would cause a miss that clears itself?
 
Perhaps you got some butter on it ?
 
She ran BEAUTIFULLY on the way to work this AM. Seems to have better power, is smoother and got a little better mpg.

I hate it when issues correct themselves........
 
LS4me said:
They were the NGK Iridium something or other. There were many warnings to NOT gap them. They are pre-gapped at .44" anyway.
Click to expand...

I don't know about not being able to gap them, but pre-gapped doesn't mean anything. I've purchased a lot of pre-gapped that aren't correct. Did you at least check them?
 
LS4me said:
They were the NGK Iridium something or other. There were many warnings to NOT gap them. They are pre-gapped at .44" anyway.
Click to expand...

Quite the voltage to span a gap of almost half an inch :eek:

Maybe the "spark knock" you heard was the pistons setting the gap for you.

:p
 
pektel said:
Quite the voltage to span a gap of almost half an inch :eek:

Maybe the "spark knock" you heard was the pistons setting the gap for you.

:p
Click to expand...

:eek::p:eek::p

That wouold be .044. That may be the wrong number anyway. In any case NGK gave at least two specific warnings to not gap the plugs.
 
LS4me said:
They were the NGK Iridium something or other. There were many warnings to NOT gap them. They are pre-gapped at .44" anyway.
Click to expand...

Even at 0.044", that is outside of spec for the LS. That adds stress to the coils and makes them more likely to experience internal high voltage breakdown of the insulation.
 
joegr said:
Even at 0.044", that is outside of spec for the LS. That adds stress to the coils and makes them more likely to experience internal high voltage breakdown of the insulation.
Click to expand...

I was just guessing. I thought I read somewhere that was the correct gap.


In any case, the "problem" seems to have vanished/corrected itself. I guess I'll leave well enough alone.
 
Could excess dielectric grease on the plug cause this? I noticed the plugs I removed had greasy tips.
 
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