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Causes of rough Idle.....

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Old 03-26-2008, 09:18 PM
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Default Causes of rough Idle.....

All right guys, I have been having a problem with my car ever since i bought it. The cars runs and idles smooth when cool, but once warmed up, it idles a little rough and the RPMs fluxuate between 700-500. The motor sputters, but doesnt act like its gonna die, and when driving, under throttle it runs great. It tends to get worse when the car is at idle in reverse and drive. I checked the plug wires and they are all fine, and just replaced the plugs. I cleaned the MAF sensor, and added a new fuel filter. It was throwing a random missfire code before the plug change, but went away the day after. You guys have any suggestions??
Old 03-26-2008, 09:40 PM
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Everybody says they checked the wires and they are fine. How did you check them? By looking at them for bad spots? You can't tell if wires are good by looking at them. They can have breaks inside that can't be seen. They aren't really made for putting on and off multiple times. The act of removing them is hard on them. I would advise changing them every other plug change.

I myself change the wires every time, but that's just me. Get a second opinion, but the wires are what I would do.
Old 03-26-2008, 10:13 PM
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IAC solinoid! its right on the throttle body! that controls your idle rpm! that can change your rpm! try unpluging that and see if the problem goes away
Old 03-26-2008, 10:41 PM
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Alright, tried unplugging the IAC and it shot the idle rpms up to around 2000 in park, so what would that mean??
Old 03-27-2008, 12:00 AM
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ok that means the solinoid opened all the way letting in all the air it could get with the tb blade position! so was the rpm stable like that? also when i Ported my TB i noticed the iac solinoid was really dirty and full of carbon on it! you can try removing those two star screws holding it and clean it if that does not solve the problem im guessing your iac is gone!
Old 03-27-2008, 04:06 PM
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Yeah, the RPMs were a steady 2000 when i unpluged it (IAC), so i turned the car off, plugged it back in, and started the car again, and it started sputtering/missfiring and the RPMs started to fluxuate between 400-700. So what would you make of that??
Old 03-27-2008, 08:59 PM
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it sounds like the solinoid is not staying steady! lik i said remove it and before you spend the money on the new one try cleaning the inside of the old one!




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