bad plugs cause idle problem? need help

noslow86

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Dec 30, 2003
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could a bad plugs cause an idle issue i have a bad loop when cold idles at 1500 rpms then drops to 500 then idles at 1500 then drops i check the plugs and the gap is at .060 if not more. i already check vacuum hose,change iac, but now its pissing me off i pulled codes but nothing should i do a tune up. .the plugs are about 2 years old and i got ford motorsport 9 mm wires. there is a little white residue on the plugs. im ready to sell it and say **** it need help bad i already shock myself twice trying to time it by putting my hand on the cap is that suppose to happen im confused
 
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jgressley2003

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Sep 21, 2002
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noslow86 said:
could a bad plugs cause an idle issue i have a bad loop when cold idles at 1500 rpms then drops to 500 then idles at 1500 then drops i check the plugs and the gap is at .060 if not more. i already check vacuum hose,change iac, but now its pissing me off i pulled codes but nothing should i do a tune up. .the plugs are about 2 years old and i got ford motorsport 9 mm wires. there is a little white residue on the plugs. im ready to sell it and say **** it need help bad i already shock myself twice trying to time it by putting my hand on the cap is that suppose to happen im confused

Sounds like an Idle Air Control valve to me.
 

ss93cobra

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A bad plug would cause a miss, which would slightly affect idle quality, but it wouldn't cause it to idle up and down as you've discribed. Regarding you getting shocked, no, that is not supposed to happen. Do you have the boot covering the dist. cap? Is the dist. making good contact with the block or is it covered in sludge? Plug gap is too big as well. I'd say look for a vacuum leak, even though you state you already have.
Any mods done to the car?
 

jrichker

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See the sticky "Help me create the Surging Idle Checklist" at the top of the forum for help with your idle problems.
 

18mustangs

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noslow86 said:
could a bad plugs cause an idle issue i have a bad loop when cold idles at 1500 rpms then drops to 500 then idles at 1500 then drops i check the plugs and the gap is at .060 if not more. i already check vacuum hose,change iac, but now its pissing me off i pulled codes but nothing should i do a tune up. .the plugs are about 2 years old and i got ford motorsport 9 mm wires. there is a little white residue on the plugs. im ready to sell it and say **** it need help bad i already shock myself twice trying to time it by putting my hand on the cap is that suppose to happen im confused

You're plug gap may be too big at 0.060, the factory specs are 0.050, but then I didn't see your mods in your sig so I can't say for sure. Do you have an aftermarket cam? Sometimes that is the culprit.