Rought idle...

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03-19-2009, 05:57 PM

NastyEvolution2006

Thread Starter

Join Date: Nov 2008

Location: CO

Posts: 23

Rough idle...

After I had the alternator replace, the V6 started to idle rough while idling in park or in drive with the brakes applied.

Jumps up and down between about 400-700 RPM.

Any thoughts?

Last edited by NastyEvolution2006; 03-22-2009 at 12:48 AM.

03-22-2009, 12:28 AM

NastyEvolution2006

Thread Starter

Join Date: Nov 2008

Location: CO

Posts: 23

Bump... Anyone?

03-22-2009, 01:02 AM

StickShifty

5th Gear Member

Join Date: May 2005

Location: New Jersey

Posts: 4,536

is it just plain idling rough, rpm goes up and down, or a combo of both.

a good start would be to clean the TB with TB cleaner, and clean the MAF with MAF cleaner. see what that does.

03-22-2009, 05:23 AM

Smooth_J

4th Gear Member

Join Date: Mar 2005

Location:

Posts: 1,538

Quote:

Originally Posted by StickShifty

is it just plain idling rough, rpm goes up and down, or a combo of both.

a good start would be to clean the TB with TB cleaner, and clean the MAF with MAF cleaner. see what that does.

+1

The PCM could be on relearn as well since you just had it replaced. Scan with the X-Cal2 and let us know. Also, whats the interval like between high and low idle?

Last edited by Smooth_J; 03-22-2009 at 06:00 AM.

03-22-2009, 11:50 AM

NastyEvolution2006

Thread Starter

Join Date: Nov 2008

Location: CO

Posts: 23

The RPM's just go up and down about every 20 seconds or so. Idles at 700 then drops to 400, then back up to 700.

Rinse, lather, repeat every 20 seconds or so...

03-22-2009, 12:37 PM

mxg30

2nd Gear Member

Join Date: Aug 2008

Location: Florida

Posts: 233

Quote:

Originally Posted by NastyEvolution2006

The RPM's just go up and down about every 20 seconds or so. Idles at 700 then drops to 400, then back up to 700.

Rinse, lather, repeat every 20 seconds or so...

Read your first post and seems odd this would be the result of an altenator change, though rule nothing out. I agree with the replies on cleaning the throttle body. I had a simular issue with hard starts & rough idle so after cleaning the Throttle body (take it off) my issue was resolved. The difference was huge. Word of caution: Be very careful cleaning the MAF as it is a very sensitive piece.