jumping engine speed at idle

[JakubK]

Hello everyone, I have a BMW M3 E 93 from 2010. My problem is that after the car warms up, the revs start to jump. it doesn't always happen, but it is very annoying because the car sometimes turns off by itself. sometimes the car turns off after opening the fuel filler. Have any of you encountered such a problem? please help

[MineralWhiteF80]

It's hard to say for sure based on exactly when it occurs, but normally the common parts consistently associated with a bouncing idle are the Idle control valve, fuel breather valve, and the throttle actuators. Identifying exactly which one might fix your issue can be difficult, but since you said removing the gas cap has made the car stall, maybe start with the fuel breather valve since it's the easiest and cheapest part to replace. Depending on how many miles your car has could help narrow it down further, it's just impossible for anyone to really diagnose anything sight-unseen on the internet.

Here are few threads for you to read through for the ICV and Fuel Breather Valve replacement.

Fuel Breather Valve:
https://www.m3post.com/forums/showthread.php?t=1273927

Idle Control Valve (Device)
https://www.m3post.com/forums/showthread.php?t=842102

[JakubK]

I have already bought a breather valve. Do you think these two errors may be related to this problem?

12 Engine electronics

278D: Generator communication
2B58: Idle controller monitoring

[MineralWhiteF80]

Originally Posted by JakubK

I have already bought a breather valve. Do you think these two errors may be related to this problem?

12 Engine electronics

278D: Generator communication
2B58: Idle controller monitoring

Im purely speculating here, but it's very likely that the 2B58 code and a bouncing idle/engine stalling could be causing the 277D generator (alternator) fault if the engine speed drops below the alternator's normal operating condition threshold.

When you say you bought a breather valve. Do you mean you have INSTALLED a breather valve already, or you have purchased one but not installed it yet?

[JakubK]

I will instal it this weekend. I'll let you know if it helped. Thank you so much for help 💪🏻

[JakubK]

that was the solution, now it works fine. thank you very muchthat was the solution, now it works fine. thank you very much