[bake]

Have been having an issue with my 2011 535i for some time now and have been hesitant to bring the car in as I don't really like leaving it up to a mechanic to diagnose a problem as I haven't always had good experiences with them being able to figure it out correctly on the first try. Anyhow here is the scenario.

On cold start the car idles high as it normally does, but then after about 30 seconds when the RPM's drop, my RPM's dip even lower almost to the point where the car feels like it is going to stall. It stumbles a bit, and then the RPM's stabilize back up to about 650. At that point the idle is a bit lumpy, but not too bad. I also notice that my exhaust tone is slightly louder than it used to be, almost like the timing is just a tad off. In my quest to figure out the problem I have removed my Stage 1 tune, changed spark plugs and ignition coils, but the problem still persists. On warm startup it does the same thing, but the RPM dip is not as severe. Otherwise the car performs fine. Anyone have any ideas before I bite the bullet and bring it in?

[Kwood-F10-535i]

O2 sensor, MAP sensor, Dirty injectors. Have you pulled any codes with ISTA?

[ezaircon4jc]

I had a similar thing happen to our 2012 535i. Turned out to be some bad gas. Did you fill-up recently? Same or different station (not that that matters much as my issue was from the same station)?

Miles on the plugs, coils, air cleaner or any other intake items?

[bake]

Originally Posted by Kwood-F10-535i

O2 sensor, MAP sensor, Dirty injectors. Have you pulled any codes with ISTA?

No codes. I used an injector cleaner a few times and didn't get any improvement. O2 sensors or MAF maybe?? But I would think those would throw codes.

[bake]

Originally Posted by ezaircon4jc

I had a similar thing happen to our 2012 535i. Turned out to be some bad gas. Did you fill-up recently? Same or different station (not that that matters much as my issue was from the same station)?

Miles on the plugs, coils, air cleaner or any other intake items?

Definitely not just bad gas. Been having this problem for about 8 months now. Just did plugs and coils, so that can be ruled out. Running a BMS intake, but have had that in the car for 4 years now and that never gave any problems.