: Idle issues, could use some input if you have any

08-03-13, 08:34 PM
I have an '06 sts with 130,000 miles , at idle it has an intermitten miss or rough idle , some times its smoothe as silk, the only code was clean throttle body, did that, even put on a new one , didn't help. Put the old one back on and cleaned the Mass air flow senser , didn't help. there are no lights on dash, again the only code is clean throttle body, this with an OBD tester at O' rieley's. Any one have any suggestions?

08-04-13, 02:13 AM
Replace maf?

08-04-13, 08:10 AM
thanks , that what i was planning, just wanted a second opinion

08-04-13, 08:40 AM
Last time you did plugs and checked the coil boots for carbon tracking ??? Are you very sure there are NO air leaks in the intake ducting at or after the MAF ??

08-04-13, 09:21 AM
What is the exact code being thrown. PXXXX?

08-04-13, 01:09 PM
Check the intake manifold bolts. They are notorious for loosening up and causing all kinds of intermittent intake leaks.

08-04-13, 06:30 PM
I just got my car back from getting both motor mounts replaced. I was having occasional vibrations that eventually got worse. It was especially noticeable at idle, but since getting the mounts replaced I've noticed my ride is so much smoother too! Drastic change and my idle is sooo smoth now! - Just a thought.

08-04-13, 09:29 PM
Thanks for the thoughts, i'll check the intake . I dont beleive its the mounts , its to intermitten I believe

08-04-13, 09:52 PM
Vacuum leaks can also mess with your idle. Not sure if BAP or MAP car, but that can also effect Idle.

08-05-13, 02:36 PM
Knowing which engine you have could be helpful, you should update your signature to include this, or specify when you ask questions.

I agree with checking the intake manifold bolts, especially if you have the N*. These are well known to have idle issues and a hesitation when cold on acceleration if these are loose. Most members who have actually checked them have found loose bolts, in many cases, several were finger tight at best. There are several threads about this topic. Torque them all to spec, in the correct order and monitor from there. What ever you do, don't over torque in an effort to trying to prevent them from loosening off later. You'll likely damage the intake and/or gaskets ability to seal properly if you do.

08-06-13, 09:17 PM
^^^ If they've been over-torqued, you may need a new intake manifold gasket.

08-07-13, 08:00 PM
^^^ If they've been over-torqued, you may need a new intake manifold gasket.
Yup, dealer over tourqed mine while trying to resolve the lean condition issues I was having. they had to replace the gasket on mine.

08-09-13, 10:43 PM
Well changed the MAS run great 99% of the time, when I first start up idles rough till after a few revs then its fine except twice in the last two days the idle roughened up for a second then was fine again. Thinking maybe vaccum leak ,but If it were a vaccum leak wouldn't idle rough always? Or at least more often. Maybe the EGR going bad. Any thoughts ?

08-10-13, 04:19 AM
So once again, did you check the intake manifold bolts and if so, what did you find? You still have said nothing about which engine you have. Yes, it could be a vacuum leak which is why the topic of the intake manifold came up. The degree of leak may be temperature related so severity of the rough idle can vary and/or be non-existent.

08-10-13, 06:18 AM
Sorry, I have the 3.6, and yes the intake was tight

08-12-13, 07:45 AM
Fineally threw a code, #4 plug missfire, possably cracked, changed it out running like new, I would have never guessed that since the plugs were new, but glad its fixed. Thanks for all the replys, its good to know there are lots of willing to help owners out there.

08-12-13, 08:10 PM
Good to hear this is resolved. I'm not overly familiar with the 3.6L engine, but a bad plug will do it. Some scan tools have the ability to show you a real-time count of misfires. This can be really helpful in a case like this since not all misfires that create an intermittently rough idle will set a code. I have heard of a few instances when a brand new plug was bad.