Hey all, been awhile. My 2009 xD is up to about 21K miles and, for the most part, running great. Every once in awhile though the idle speed becomes extremely inconsistent, even after the engine has warmed up. It's an intermittent issue and I haven't noticed any pattern to it.

Even when it is acting up, there's no defined pattern. If I take it out of gear, sometimes it will settle around 700rpm like normal. Sometimes it will be closer to the 1200rpm that's normal when the car is warming up, and sometimes it will rev up to about 2000rpm.

This will come on suddenly, last until I shut off the car, and be gone the next day. It's infrequent but it kinda bothers me. Does anyone have any idea what I should check? Last time it happened was a few days ago, and the temperature was hovering just above freezing, so it wasn't insanely cold.

 

air conditioner or heater? each click of the a/c brings my rpms up slightly at idle

 

maybe the belt to the pulley has been adjusted. kinda throws the rpm level as well.

 

that wouldnt make it change intermittently while driving, where as your a/c levels will

 

Same thing as I was thinking, sounds like the A/C compressor is cycling on and off.

 

Yeah, or you're probably using the defroster which turns the compressor on as well.

 

It shouldn't go up to 2,000 RPM, though... I would take it in while it is still under warranty. No sense in leaving it until you have to PAY to get it fixed. It could be something simple or something really expensive.

 

mine does that when I'm using defog

 

Just had my 2009 xD in for a check engine light on at 20K miles. There was a TSIB on a "retarded spark" at low RPMS, although my car was running seemingly fine. After the update, the car stumbles far less at low RPMs when starting in 2nd gear; it honestly sounded like diesel motor for a second or two if I didn't floor the pedal or was smooth enough on acceleration after letting the clutch out.

Ironically, the TSIB was issued on the very same day I bought the car: June 19, 2009. It consisted of an ECM flash and a "decarbonization" of the throttle body (wiping it with a rag and spraying a dash of throttle plate cleaner for good measure).

 

While mine is warming up, only in cold temps, below 20.F my idle will infrequently jump up to 2k, and sometimes bounce from 1-2k for a few seconds. Called multiple dealers and all said that was normal. Still bothers me, let me know what they say..

 

i think it's the engine "rev'ing" itself to get warmer faster. As opposed to people doing it and hitting 3000+ RPM's to rev...

 

Finally reporting back in, though there's not much to say. I've not been able to duplicate this, it happens on infuriatingly rare intervals.

I have not been running the AC as such, but I have been frequently using the defroster. That does cause the idle speed to increase a little, but that's a steady increase from about 700 to 900 rpm and it does not cause the uneven idle.

I have not taken it in to the dealer. Back when I took my car in for the first free oil change the dealership managed to botch it up and they were completely apathetic when I called to complain (I'm pretty sure they put 10w50 oil in there, and they definitely overfilled the crankcase). If they can't even get an oil change done right, I'm not willing to take my car back to them for anything. I might make a road trip to the next town to see about an ECM flash as Tracompa3 mentioned and ask them about the idle at the same time.