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Old 10-21-2009, 08:21 PM   #1
Go350zGo
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Question How Rough is a Rough Idle

mods, if you feel that this is a redundant topic, youre welcome to delete it.

basically, what are the genuine characteristics of a rough idle? sometimes i think im getting it, but am not sure as to what is the general sign. im assuming the car shakes pretty violently, but how violent? if it is gauged by RPMs, what RPM range is it attributed to? im assuming that it varies from case to case; but im wondering if there are some basics that make it a dead giveaway? if there are specific sounds that come from the engine, what are they? the reason i ask these questions is because i find myself reading into a lot of threads on rough idles. i get what to check for as far as cylinder misfires and other potential engine failures, but is it possible to just have a rough idle with everything else being?

once again, sorry if this is dumb, but i am very curious. thanks!
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Old 10-21-2009, 11:01 PM   #2
Uncle Scotty
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is the check engine light on???
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Old 10-22-2009, 03:12 AM   #3
Go350zGo
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negative
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Old 10-22-2009, 03:29 AM   #4
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i think i get what you're saying OP,
NOT a problem you're currently having just wondering about what its like?

sometimes rough idle is idle dropping like 200rpms then coming back then down and back while you're sitting still. for me rough idle is when my car idles just a few rpms off(like 50-100) and it causes my car to shake just a tad.
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Old 10-22-2009, 07:21 AM   #5
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run some fuel injector cleaner through it
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Old 10-22-2009, 03:30 PM   #6
Go350zGo
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Quote:
Originally Posted by JamesBernard View Post
i think i get what you're saying OP,
NOT a problem you're currently having just wondering about what its like?

sometimes rough idle is idle dropping like 200rpms then coming back then down and back while you're sitting still. for me rough idle is when my car idles just a few rpms off(like 50-100) and it causes my car to shake just a tad.
yup, thats basically what im getting at exactly
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Old 10-22-2009, 05:37 PM   #7
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poor grounding???
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Old 10-22-2009, 06:56 PM   #8
Go350zGo
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very interesting that you say that, because for some reason my car came with a grounding kit(i bought it used). this confuses me tremendously if that is the case. i have seen VERY few subarus with a grounding kit.

on another note scotty, run fuel injector cleaner through what?
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Old 10-22-2009, 07:09 PM   #9
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Not to jack the thread but I have the same question. I had purchased my friend's hyper voltage system and once installed, my idle became rougher. I had increased my idle RPM by 50 and it seems to level off okay. Shouldn't the grounding kit make the vehicle's idle smoother?

BTW Run fuel injector cleaner through your gas tank.
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Old 10-22-2009, 07:59 PM   #10
PIGSTI06
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Hunting Is Idle Minus 50 Rpm And Surging Is Idle Plus 50 Rpm
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Old 10-22-2009, 10:35 PM   #11
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Quote:
Originally Posted by Go350zGo View Post
very interesting that you say that, because for some reason my car came with a grounding kit(i bought it used). this confuses me tremendously if that is the case. i have seen VERY few subarus with a grounding kit.

on another note scotty, run fuel injector cleaner through what?
are ALL the accessories OFF when this happens???

if you have the AC on when it does this, then
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Old 10-22-2009, 11:28 PM   #12
Go350zGo
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Quote:
Originally Posted by Uncle Scotty View Post
are ALL the accessories OFF when this happens???

if you have the AC on when it does this, then
lol i haven't turned my AC on in like 4 months. im not that dumb lol, no accessories are on

Quote:
Originally Posted by PIGSTI06 View Post
Hunting Is Idle Minus 50 Rpm And Surging Is Idle Plus 50 Rpm
so youre saying that what im describing is normal? please elaborate, sounds promising
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