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perpetual college student
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3,903 Posts
Discussion Starter #1
does it hurt the car? detonation? poor gas mileage?
 

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perpetual college student
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3,903 Posts
Discussion Starter #2
come on, surely someone knows
 

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14.1 @ 100mph N/A
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5,289 Posts
Nothing whatsoever. When Jamie and I changed our spark plugs, they were all eroded to .070-.080, and the car had been running great. Now they're at .042 and there's no difference
 

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perpetual college student
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3,903 Posts
Discussion Starter #4
then why do different cars have different plug gaps? Why isn't it just standard on all NA cars to gap to .100 ? :D I'm just wondering because on my g/f's car ('97 Escort :D) I changed the plugs and the sticker was missing (and no manual) that said what gap to put them at, and I got conflicting reports from dealerships about what gap to use (.048 vs. .052-.056) so I just used .052 -- and was thereby wondering about any effects.

thanks for the reply though :)
 

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14.1 @ 100mph N/A
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5,289 Posts
Different ignitions have different strengths, so they require different gaps. Most modern fords use .052-.054. .048 is too small. It won't make a differene in how the car performs unless it's EXTREME one way or another. High compression and forced induction engines are more sensitive to gaps, as well as cars with weak ignitions, like old single coil GM and Chrysler. You can't take them over .035.

On a car with hard to reach plugs, go with the tightest gap allowed so the plugs will stay within spec as the electrodes wear.
 

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134 Posts
well then what is the standard gap on the plugs on a N/A. I have denso platnums in and since I chaged them the car has just not felt quite right. And the dealership says there is a miss in the idle. Can this be caused by the gap. I Know I shoudn't have but I just put them in strait from the box :eek:

Have Fun,
Chris
 

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14.1 @ 100mph N/A
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5,289 Posts
.039-.043 is standard. Find out what the plugs are gapped at.
 

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Once again you are awesome. if the plugs are really out can this cause a miss?

Have Fun,
Chris
 

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14.1 @ 100mph N/A
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5,289 Posts
Only if they're WAY off. Like I said above, when I changed my plugs, they were worn to .070-.080, and the car had been running fine. Describe the "miss". Pull one front plug and check the gap.
 
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