328i Idle Surging (Video)

rba262 · 06-07-2021, 07:19 PM

My e92 328i will have an occasional idle surge when coming to a stoplight. This happens mostly in the morning when the engine is cold and the AC is on.
It does not do this every time I drive the car but has been getting more common recently

Managed to get a video of it today and wondering if anyone has experienced something similar.

The idle usually moves a little (+/- 50 RPMs) on cold starts and when the engine is warming up but once oil is up to temp this rarely happens.
The 500 rpm surging shown in this video only happens when coming to a hard stop or sometimes shifting into reverse.

The car has never thrown a code but I honestly wish it would lol.
Any tips or suggestions would be appreciated before I take it to a shop.

Already changed the Coils / Plugs, Cleaned the MAF and Solenoids

Glene · 06-08-2021, 01:50 PM

Clean out the vanos solenoids and the check valves. Just remove them and spray them with brake cleaner.

rba262 · 06-08-2021, 10:27 PM

Update, it was a vacuum leak coming from the valve cover.

06-07-2021, 07:19 PM	#1
rba262 Registered 0 Rep 3 Posts Drives: E92 Join Date: Nov 2020 Location: Ohio iTrader: (0)	328i Idle Surging (Video) My e92 328i will have an occasional idle surge when coming to a stoplight. This happens mostly in the morning when the engine is cold and the AC is on. It does not do this every time I drive the car but has been getting more common recently Managed to get a video of it today and wondering if anyone has experienced something similar. The idle usually moves a little (+/- 50 RPMs) on cold starts and when the engine is warming up but once oil is up to temp this rarely happens. The 500 rpm surging shown in this video only happens when coming to a hard stop or sometimes shifting into reverse. The car has never thrown a code but I honestly wish it would lol. Any tips or suggestions would be appreciated before I take it to a shop. Already changed the Coils / Plugs, Cleaned the MAF and Solenoids
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06-08-2021, 01:50 PM	#2
Glene First Lieutenant 64 Rep 323 Posts Drives: 335is Join Date: Dec 2018 Location: Michigan iTrader: (0)	Clean out the vanos solenoids and the check valves. Just remove them and spray them with brake cleaner.
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06-08-2021, 10:27 PM	#3
rba262 Registered 0 Rep 3 Posts Drives: E92 Join Date: Nov 2020 Location: Ohio iTrader: (0)	Update, it was a vacuum leak coming from the valve cover.
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