[Bimmer Pleaser]

E92 N52. I am getting occasional RPM fluctuations after hard decelerations. They are very rare but happen now and then. One time even car turned off after a hard stop in highway (80 to 0 mph) due to traffic jam. No warning lights or codes.

Car accelerates and drives fine. I know it’s hard to guess the culprit but any suggestions? I want to be proactive and fix an impending problem.

Thanks

[Indyeah]

Is the idle normal?
First thing that pops into my mind when I hear RPM flux is the MAF. Disconnect it and drive without it for a while and see if still does what you are describing. Can of MAF cleaner is a couple bucks. Could try that as well.

[Bimmer Pleaser]

Originally Posted by Indyeah

Is the idle normal?
First thing that pops into my mind when I hear RPM flux is the MAF. Disconnect it and drive without it for a while and see if still does what you are describing. Can of MAF cleaner is a couple bucks. Could try that as well.

Thanks for the reply. Idle is fine 95% of time but very rarely I see these RPM fluctuations. Also after hard deceleration, again rarely.

[gster109]

Originally Posted by Bimmer Pleaser

Thanks for the reply. Idle is fine 95% of time but very rarely I see these RPM fluctuations. Also after hard deceleration, again rarely.

could be an issue with your vacuum hoses or worst case scenario it's your vanos solenoids

[xiaodong1102]

could be vanos issue? just guess

[Bimmer Pleaser]

is there a way to narrow down the cause? I am guessing just clean the up the solenoids first?