Have developed a rough idle. Cause/Fix?

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KMeloney

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Hey all,

Lately (within the last couple of months) I have developed a rough idle in the '09. The engine is back to stock (no Volant or tune). Sitting at a light, for instance, the RPMs sit right on the 500 line, and I can feel a little bit of a shudder through my seat/the vehicle. The RPMs don't bounce at all -- the needle simply sits covering the hash mark.

What could cause this, and what is the fix? Am I idling a tick low?

I ran a bottle of Techron through the fuel system with my last partial fill up. I haven't noticed any change.

Any help is appreciated!
 

Zed 71

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Since you have been swapping out the intake a few times, have you checked the MAF or throttle body?
 

Faceplant

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I have the exact same issue. Only in drive though. If I put it in Neutral it stops shuddering. I would NOT put any additives (Lucas oil or otherwise) in any vehicle I own. Just my .02.
 

02Lightning

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No... What am I checking for? Thanks.

Get some MAF cleaner (can get a can at autozone) and spray it down real good. Some times oil from the oiled air filter will get on the MAF and make it run bad.
 

Zed 71

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^ yeah inspect the MAF wire for any dirt, film, etc. Be careful because the MAF is sensitive. In regards to the throttle body, just see if it is dirty and needs cleaning. Then check all intake piping connections to make sure they are on tight with no leaks. A dirty MAF and sticky throttle body can cause the engine to idle rough. Just some easy stuff to take a look at.
 
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KMeloney

KMeloney

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I'll check it out, folks. Thanks.


Sent from my iPhone using Tapatalk
 

fellowgearhead

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Ditto what the others said about the MAF sensor. Cleaned ours a couple of months ago and the problem went away.
 
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KMeloney

KMeloney

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I JUST sprayed mine down at lunchtime today. The brief ride back to the office suggested that the idle is better. I'll keep an eye on things and see if this did the trick. Thanks, folks!
 

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