Rough idle 99 M6
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Pro
Joined: Jan 2005
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From: Endicott New York
Oldtimer
Rough idle 99 M6
Bought my first C5 (99 6speed) a little over a month ago (moved up from a 94 A4). Has 57,XXX miles on it. Runs fine but in my opinion the idle seems a little rough. It doesn't miss, just seems a bit rough to me. Is this normal?
Tech Contributor
Joined: Jan 2007
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From: Dyer, IN
Plugs/wires
fuel/air filter
belts/hoses as required
Fluids
PCV valve+plus full inspection of all vacuum lines
It's a few hundred up front, but it gives you a starting point for everything.
Last edited by lucky131969; Jul 12, 2010 at 11:33 PM.
Tech Contributor
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From: Should this thoughtful, valuable contribution meet with no acknowledgement or 'thanks' this post----
Start by cleaning the air filter...if it has a Blackwing it's probably plugged with dirt/dust. You will be amazed at the difference this makes...everyone seems to overlook this simple step, but it is vital to getting air into the engine and giving back hp and idle smoothness. If that doesn't help, get back to me...there are other things you can do.
Thread Starter
Pro
Joined: Jan 2005
Posts: 705
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From: Endicott New York
Oldtimer
Start by cleaning the air filter...if it has a Blackwing it's probably plugged with dirt/dust. You will be amazed at the difference this makes...everyone seems to overlook this simple step, but it is vital to getting air into the engine and giving back hp and idle smoothness. If that doesn't help, get back to me...there are other things you can do.
Tech Contributor
Joined: Aug 1999
Posts: 16,376
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From: Should this thoughtful, valuable contribution meet with no acknowledgement or 'thanks' this post----
Thread Starter
Pro
Joined: Jan 2005
Posts: 705
Likes: 6
From: Endicott New York
Oldtimer
Ok, next you should look into cleaning your MAF screen and the fragile little wires inside. Get a can of CRC MAF cleaner, take everything apart, and follow the directions on the can. Crud on the wires will cause incorrect readings and the computer will not perform properly...it doesn't take much to cause a problem.
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Drifting
Joined: Oct 2005
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From: Terrell North Carolina
A slight rough idle is normal for the early LS1 engines. I have had a 2000 from day one and it has a slight rough idle and every 1997 to 2001 I have had listened to had a slight bump in the idle. When the engine went to 350 hp, the idle was smoothed out quite a bit. Anyway, from what you describe, I say it is a normal idle.
Racer
Joined: May 2010
Posts: 300
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From: rochester new york
Ok, next you should look into cleaning your MAF screen and the fragile little wires inside. Get a can of CRC MAF cleaner, take everything apart, and follow the directions on the can. Crud on the wires will cause incorrect readings and the computer will not perform properly...it doesn't take much to cause a problem.
if the MAF sensor is contaminated, there will be a " lean bank one, lean bank 2 '
Tech Contributor
Joined: Aug 1999
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From: Should this thoughtful, valuable contribution meet with no acknowledgement or 'thanks' this post----
I became a believer when this stuff solved my rough idle. Here's a video that is a bit commercial, but informative. For us corvette guys it makes some good points to think about, especially the deposit of air filter oils onto the wires. All I know is when I cleaned the maf with this stuff the car ran like a jackrabbit and idled smooth as hell...hope this helps you. If not you can look into other areas too.
http://www.youtube.com/watch?v=vPT8rL0noYg
http://www.youtube.com/watch?v=vPT8rL0noYg
