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Hello everyone,

I'm planning on doing my spark plugs in my 05 Civic LX Special Edition Sedan in the next few days. My car has 120K on the odometer. I purchased the NGK PZFR6F-11 from amazon and got the plugs for about $9.00 each, so I didn't break the bank by paying $24 each at my local dealer.

I checked the gap on the 4 plugs I got and the gap is .040 (using the small round spark plug gap tool). I know that OEM Spec is .043.

My question is, do I need to increase the gap by .003 or can I leave it alone?

I read on several other post that the tip/electrode is very fragile on these plugs, so I don't want to mess around and ruin the plugs. The box also has a pic/diagram showing not to try and gap these.

Should I leave the plugs alone or gap them?

Thanks.

 
Rep Power: 517

Leave it alone, that's close enough it won't cause problems. IMO

 
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Thanks, Ezone.

What are some symptoms if the gap is an issue? Just for my knowledge if after I do the install and experience odd behavior.

Thanks.

 
Rep Power: 517

Misfire issues that are resolved by correcting the gap.

Note, misfires can have many different causes so you shouldn't automatically jump to a conclusion like that without just cause

 
Rep Power: 517

Come to think of it....the Fit my GF is driving now is running on plugs gapped less than spec by about 0.2mm.
Spec was 1.3mm, it's running fine on plugs with 1.1mm gaps.

 
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Thanks Ezone.

I just wanted to make sure I wouldn't have any problems. It sounds like a very small difference is fine, but a significant difference could cause problems.

I'm hoping to do the install today if the rain letup. It looks like a quick 30 min job if I don't run into any problems like a stuck plug.

Thanks.

 
Rep Power: 517

Have you ever checked the accuracy of your gapper wheel? (using a micrometer)
They are so cheap it wouldn't surprise me if it isn't perfect.

 
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You beat me to the punch, Ezone. I was gonna say I bet my tool was not accurate. I have two of the gap tools and one puts the spark plugs really close to .043, whereas the other puts them all at .040. They are all installed and it took about 10 minutes total. I started the car, and it cranked like usual.

Below is a pic of the old spark plugs. They don't look bad, but two plugs have darker tips than the other, and all 4 are scorched at the bottom of the porcelain. Do these old plugs look like they aged fine or is there an indication of a possible problem?

Thanks.

 
Rep Power: 517

The stains ("scorch") above the hex is corona stain, that's normal.

The one with blackened threads may have been a bit loose and allowed carbon to creep up the threads.

 
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Thanks Ezone. Everything seems all good. I drove around for a few hours (put on about 45 miles) and the car feels great. Shifts good and accelerates good too. Not sure if this is an improvement over before, but with the old plugs in, the car drove fine too. No complaints.

Thanks.