Cold start - rough idle - MIL light
02-27-2017, 10:45 AM
#21
Keep in mind that is Canadian $'s.
I have been having this issue recently too. Car has 121k on it. I'm not so worried about the longer crank as it is cold and a longer crank is normal. I have been getting a rough idle immediately after a cold start, the car shakes, and after the idle goes from 1200 rpm on start-up down to about 950 rpm(about 4-5 seconds) the idle smooths and the car drives fine. I have gotten a CEL which I have not had scanned. Some things I'm weighing though:
A: I am typically driving less than 7 miles at any given time right now.
B: I don't typically drive like I did 10 years ago (more casual with a very occasional throttle application of more than 50%)
C: I recently drove the car at highway speeds for about an hour. After the car sat for several hours, that following cold start-up was smoother, and in the days following it seems to have been cured
D: A week ago, my battery status in the MMI was under 50% for a couple days
E: I don't know how old my battery is
F: Coils, Plugs, and Fuel Filter were all replaced at 116k.
All of the above stated things are going through my head when this happens. I'm not sure if the issue is carbon buildup as I drive somewhat causally most of the time, or if the battery is getting weak.
I have been having this issue recently too. Car has 121k on it. I'm not so worried about the longer crank as it is cold and a longer crank is normal. I have been getting a rough idle immediately after a cold start, the car shakes, and after the idle goes from 1200 rpm on start-up down to about 950 rpm(about 4-5 seconds) the idle smooths and the car drives fine. I have gotten a CEL which I have not had scanned. Some things I'm weighing though:
A: I am typically driving less than 7 miles at any given time right now.
B: I don't typically drive like I did 10 years ago (more casual with a very occasional throttle application of more than 50%)
C: I recently drove the car at highway speeds for about an hour. After the car sat for several hours, that following cold start-up was smoother, and in the days following it seems to have been cured
D: A week ago, my battery status in the MMI was under 50% for a couple days
E: I don't know how old my battery is
F: Coils, Plugs, and Fuel Filter were all replaced at 116k.
All of the above stated things are going through my head when this happens. I'm not sure if the issue is carbon buildup as I drive somewhat causally most of the time, or if the battery is getting weak.
You most definitely will have carbon build-up, which is only getting worse with the distance you drive and your manner of driving. But once, you have carbon it's not as easy as simply driving the car "hard" a few times to remedy the issue...it's backed on and it really does require physical intervention to remove it.
I did a write-up on carbon build-up awhile back, here's a link to it:
https://www.audiworld.com/forums/a6-.../#post24581323
09-20-2017, 12:07 PM
#22
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Join Date: May 2016
Location: Chester Co., PA
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Keep in mind that is Canadian $'s.
I have been having this issue recently too. Car has 121k on it. I'm not so worried about the longer crank as it is cold and a longer crank is normal. I have been getting a rough idle immediately after a cold start, the car shakes, and after the idle goes from 1200 rpm on start-up down to about 950 rpm(about 4-5 seconds) the idle smooths and the car drives fine. I have gotten a CEL which I have not had scanned. Some things I'm weighing though:
A: I am typically driving less than 7 miles at any given time right now.
B: I don't typically drive like I did 10 years ago (more casual with a very occasional throttle application of more than 50%)
C: I recently drove the car at highway speeds for about an hour. After the car sat for several hours, that following cold start-up was smoother, and in the days following it seems to have been cured
D: A week ago, my battery status in the MMI was under 50% for a couple days
E: I don't know how old my battery is
F: Coils, Plugs, and Fuel Filter were all replaced at 116k.
All of the above stated things are going through my head when this happens. I'm not sure if the issue is carbon buildup as I drive somewhat causally most of the time, or if the battery is getting weak.
I have been having this issue recently too. Car has 121k on it. I'm not so worried about the longer crank as it is cold and a longer crank is normal. I have been getting a rough idle immediately after a cold start, the car shakes, and after the idle goes from 1200 rpm on start-up down to about 950 rpm(about 4-5 seconds) the idle smooths and the car drives fine. I have gotten a CEL which I have not had scanned. Some things I'm weighing though:
A: I am typically driving less than 7 miles at any given time right now.
B: I don't typically drive like I did 10 years ago (more casual with a very occasional throttle application of more than 50%)
C: I recently drove the car at highway speeds for about an hour. After the car sat for several hours, that following cold start-up was smoother, and in the days following it seems to have been cured
D: A week ago, my battery status in the MMI was under 50% for a couple days
E: I don't know how old my battery is
F: Coils, Plugs, and Fuel Filter were all replaced at 116k.
All of the above stated things are going through my head when this happens. I'm not sure if the issue is carbon buildup as I drive somewhat causally most of the time, or if the battery is getting weak.
Just an update. I just picked the car up for diagnosis of these issues. The shop found 4 stored misfire codes for Cylinder 3. Pulled the plug, replaced, codes went away. They also found two active codes for the camshaft position sensors. They found that one exhaust side sensor was way out of spec, and the other exhaust side sensor was inconsistent. Replaced both exhaust side camshaft position sensors (intake side sensors were perfect). All codes cleared except for one random EVAP code (Not showing active or pending.)
The plug was ~$23 and the pair of Cam sensors came to $103
Plus labor.
09-20-2017, 12:10 PM
#23
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Join Date: May 2016
Location: Chester Co., PA
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As step #1, I'd change your battery ASAP. If that is reading less than 100%, it's on it's way out and imho not worth the risk for such an easy fix.
You most definitely will have carbon build-up, which is only getting worse with the distance you drive and your manner of driving. But once, you have carbon it's not as easy as simply driving the car "hard" a few times to remedy the issue...it's backed on and it really does require physical intervention to remove it.
I did a write-up on carbon build-up awhile back, here's a link to it:
https://www.audiworld.com/forums/a6-.../#post24581323
You most definitely will have carbon build-up, which is only getting worse with the distance you drive and your manner of driving. But once, you have carbon it's not as easy as simply driving the car "hard" a few times to remedy the issue...it's backed on and it really does require physical intervention to remove it.
I did a write-up on carbon build-up awhile back, here's a link to it:
https://www.audiworld.com/forums/a6-.../#post24581323
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