I have an '05 S that I bought a couple weeks ago. So far it has been great but just went for a drive & on the way home at a light I noticed the idle was a little rough (bouncing maybe 50RPM continuously while stopped) & I had a flashing CEL. CEL went away after I started driving again but came back once stopped at home. Then off again.

Some background on the car...it is a 6 speed coupe with 94k miles & was very well maintained by the previous owner. Car does have some mods: Softronic tune, AWE cats & X51 headers.

Plugs & coils done last July (maybe 5-10k ago). On other cars I would assume plugs or coil packs maybe, but don't know anything about these engines. Is there also an ignition control module (ICM or POS) like on the Audi?

Anyone have an thoughts or experience here?

I have always used a Vag Com on our Audi's in the past to read codes & diagnose issues, but haven't bought the Durametric cable yet but plan to. Maybe sooner vs. later.

I am a DIY guy on most things. I have done everything from full coilover suspension installs, turbo kit installs, timing belt jobs on Audi's & even swapped Audi A8 transmissions in my garage, so I am not afraid to turn a wrench or tear into something.

Any advice or guidance is appreciated.

Thanks.

 

did last owner replace the IMS?

 

No, they did not replace the IMS.

 

maybe you should do a little bit searching about 05 997, some of them do have a IMS issue which is a headache, hope yours doesn't have that.
And good luck on this beautiful car

 

An OBDII code reader might show some stored codes and point you in the right direction.

 

One thing I forgot to include, this happened right after getting fuel (92 octane at Safeway - maybe not the best, but never an issue in my other cars). Car was down to about a gallon or two left & I fueled up to full & then the issue immediately after on the ride home.

I will try to read the codes with my Vag Com (Audi code reader) & see if it sees anything.

Yes, I am aware of the IMS issue, but it seems to have more of a history of occurring on lower mileage cars from what I have read. This seems more like a misfire than anything major (knock on wood).

 

did u check the water tank? Any coolant leaking?
Different gas may cause the CEL, it happened on my friend's m5....

 

I was able to pull DTC codes with my VagCom (VCDS) cable for my Audi.

Looks like misfires across all cylinders:

Thursday,21,March,2013,22:00:56:24777
VCDS Version: Release 11.11.5 (x64)
Data version: 20121222



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Mode 07: Pending emission related fault codes

Address 11 (Engine): 15 Faults Found:
P0300 - Random/Multiple Cylinder Misfire Detected
P0301 - Cylinder 1: Misfire Detected
P0303 - Cylinder 3: Misfire Detected
P0305 - Cylinder 5: Misfire Detected
P0306 - Cylinder 6: Misfire Detected
P0302 - Cylinder 2: Misfire Detected
P0304 - Cylinder 4: Misfire Detected
P0300 - Random/Multiple Cylinder Misfire Detected
P0302 - Cylinder 2: Misfire Detected
P0303 - Cylinder 3: Misfire Detected
P0301 - Cylinder 1: Misfire Detected
P0306 - Cylinder 6: Misfire Detected
P0304 - Cylinder 4: Misfire Detected
P0305 - Cylinder 5: Misfire Detected
P0301 - Cylinder 1: Misfire Detected


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OBD DTCs erased
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I cleared the codes but have not ran the car yet. I will test tomorrow & see if they return.

Any idea what would cause misfire codes across all cylinders?

Thanks.

 

No leaks anywhere I can find.

Tomorrow I will try pulling the MAF & cleaning it with MAF cleaner since the search suggests that could be an issue.

 

Gas was going to be my first thought .....

 

get a check on the stored codes...my issue was somewhat similar, intermittent CEL, jumping idle speed a couple of times...usually happened in colder weather (light would come on typically within about 5 miles from start-up when it was less than 30 degrees, not always when it would come on, but usually). My code was P0021, timing over-advanced in bank 2 (but also had a stored P0011 (bank 1). Wound up being a couple of sticky actuators...Porsche dealer replaced bank 1 and bank 2 actuators for just under $900.

 

oh, and twice the CEL came on within about 5 miles of filling with gas...but I've never put anything but Shell 93 octane in it.

 

It could be the starter cable. Mine went and I had all sorts of idle problems and misfires all over the place. Then it stopped wanting to start on a hot start.

 

Update:

This morning I pulled the MAF & cleaned it with MAF cleaner. When finishing up I noticed that the oil cap was loose (barely even on there really), so I tighened it down.

I then started the car & let it idle for a few mins. No CEL & the idle seems to be much more solid than last night. Ranging from dead solid to maybe 25 rpm movement so much better than the 50+ jump it was making last night. No shake in the cabin either so things seem better so far.

I will test more later but hopefully that was it.

 

Glad to hear and hopefully that was it. Report back in a few days and keep us updated.