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      01-04-2023, 08:03 AM   #1
Durrkey
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Strange Idle Issue

Hi all! Trying to pinpoint this idle issue I've been getting the past few months.

Cold or hot, when at a stop my F82 DCT idle (in gear or out of gear, ac on or off) will be around 700 rpm and drop down to 500ish, stutter a bit, then back up to 700. Does this about every 5 seconds or so. Other than idle it performs fine.

Has had new plugs in the last 5k when I changed out the valve cover to fix the pcv valve issue. Clean MAF sensors, disconnected/reconnected battery and let idle relearn.

Any ideas on where to look, kind of at a loss right now.
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      01-04-2023, 10:46 AM   #2
Dabeamerking
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E85? Lean or rich fuel mixture? Any tune? Are you monitoring crankcase ventilation pressure after pcv valve?
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      01-04-2023, 03:24 PM   #3
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It could be your coils!
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      01-05-2023, 12:48 PM   #4
Durrkey
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Completely stock everything. Will try all new coils next as they are probably in need of changing anyways, at about 100k on it.
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      01-05-2023, 05:59 PM   #5
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Could be an upper O2 sensor starting to go bad. If the AFR reading is off you'll get stutter at idle. You would need to use logging software to be sure. I'm only familiar with logging using Bootmod3.
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'18 F80 Base 6MT | '19 F82 Exec DCT | '18 F82 Comp Exec DCT | '23 G80cx
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      01-29-2023, 04:22 AM   #6
Hide-F80M3
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VVT motor issue?

Hello, how about valvetronic motor ? My shop told me that VVT motor issues have been increasing recently.
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      01-30-2023, 04:29 AM   #7
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Quote:
Originally Posted by Hide-F80M3 View Post
Hello, how about valvetronic motor ? My shop told me that VVT motor issues have been increasing recently.
If you hear woodpecker when entering car then yes
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