Rough idle from time to time?

[mazaa93]

Hey gents, picked up my M4 just under 2 weeks ago now.

Firstly, I have to say that the M4 is freakin' amazing. Absolutely in love with it. Constantly cracking a smile from ear to ear whenever I jump in it & give it a decent hiding!

So I've noticed from time to time I'll get a slightly rough idle where I can feel the car "kick" to the side every now and then - it's not a huge jolt, but it's enough to feel it while sitting at a red light.

Is this something I should be worried about?

[bwong6736]

a/c on? or a/c not on? i recently got my m3 about 3 weeks ago, and i noticed the same thing, I brought it to my dealership and they told me it was normal, and if anything i can bring it back, i don't notice any kick in mine but just a slight fluctuation in the idle without my a/c on.

[mrgicm]

I also feel the same in mine... time to time a slight kick... also told the dealer they said the car has no faults carry on... hmmm...

[mnhomes]

My car started doing the same thing after a couple weeks. It idles slightly rough sometimes and more so with the AC off. I noticed the Rpms drop when AC is off to 550-600rpm. Anyone else have the Rpms drop and what does it idle at with ac off? Dealer says nothing is wrong of course never did it when in the beginning.

[Marth06]

Yeah mine does it now and then...like a misfire when idling even with AC off..
But it still drives well

[mazaa93]

Originally Posted by bwong6736

a/c on? or a/c not on? i recently got my m3 about 3 weeks ago, and i noticed the same thing, I brought it to my dealership and they told me it was normal, and if anything i can bring it back, i don't notice any kick in mine but just a slight fluctuation in the idle without my a/c on.

A/C off.
I haven't driven the car in about 3 weeks now (just finished building new set of garages to make room) so I haven't tested it again.

Originally Posted by mrgicm

I also feel the same in mine... time to time a slight kick... also told the dealer they said the car has no faults carry on... hmmm...

Might be normal - everyone else in here is mentioning the same sort of thing with the A/C off.

Originally Posted by mnhomes

My car started doing the same thing after a couple weeks. It idles slightly rough sometimes and more so with the AC off. I noticed the Rpms drop when AC is off to 550-600rpm. Anyone else have the Rpms drop and what does it idle at with ac off? Dealer says nothing is wrong of course never did it when in the beginning.

I'm not sure about that problem, I haven't had the need to use the A/C just yet.

Originally Posted by Marth06

Yeah mine does it now and then...like a misfire when idling even with AC off..
But it still drives well

Exactly right - it drives perfectly, but when I'm at a stop I feel it do a little "jolt" every now and then.

[brownb_2]

yep exactly the same thing here

[andrei.m4]

Anyone found the problem for this issue with ac of? Is a real problem, bootmod indicate misfires at random cylinders.

[ChrisSTR]

I have the same feeling.. I mean what, it works better in idle with a/c on??

[andrei.m4]

I changed plugs and coil and i can t say idle is same with misfire randomly, i will install oil catch can cause in chargepipe one i have some oil and i am afraid about oil going in intake.

[GoodtoGo]

Suggest cleaning your MAF sensors with an electrical cleaner. Smoothed our my idle even though I had new spark plugs.

[andrei.m4]

I cleaned maf and map sensors, installed occ, plugs are ngk 97506 gap 0.023, bm3 stage1 93 oct, and is same, a little kick, misfire from time to time, with ac off.

[Kilabyte]

I've only noticed it while in the cold start sequence, not much but it's there sometimes. May try cleaning the MAFs since I've been running aftermarket intakes since this summer and only started noticing this recently, wasn't sure if it's the cold temps

[x.shell]

I get the rough idle once in a while too; especially oh start up.

So yesterday I ran a scan and got a couple misfire error codes.



Then I ran the scan again immediately, and I got zero errors.

[Beemerm3]

I get lumpy idle when it's cold . Cold start n all assuming it's the spark plug. I heard spark plugs go out early in these cars. So assuming ur close to buying new plugs.

[andrei.m4]

I found some info about this misfires, when the alternator not charging this happens, when it charge everithing is smooth, when it charge voltage is around 14v when not around 13.2v, somehow is related to the coils and spark power on idle... i can t figure right now.

[andrei.m4]

I watched at alternator ampere, when it drops to 0-10Ampers car start do rough idle, when i start the car it goes up 100ampere and chanrging and no rough idle. When i turn on ac ampere goes up and no rough idle, so somehow the rough idle appear when alternator is in fully standby and the spark power is lowered, my car is 2015 and never recived an update maybe updating the car the charge metod is different and rough idle goes away. Or other option si racing ignition coils or power amplifier but i can t find one for f82.

[Steveo]

Interesting on the alternator, so is the light weight battery a POS?
Would a heavy duty battery be better?

[Kefka]

I face the same "issue" with f82 -2015.

A little "kick" and very low exhaust noise.

The behavior is similar as others shared here.

[papasmurf_m3]

I just noticed this also sometimes I can feel a very slight rough idle and normally silly smooth. So I guess it’s normal?

[vbermensch]

My N54 335i has done this, and as luck will have it, so does my M3, I am not particularly concerned, as the car runs as it should.

[Josh_F82]

I noticed I'm having the same issue. I'm DPs, single midpipe, pure turbos and custom tune on 93. I still have stock intakes and my spark plugs are brand new. Oddly enough, i noticed this starting to happen after i upgraded my cold side charge pipe. The coupler kept popping off so i had to replace it with a heavier duty one with constant TQ clamps... and that's when i noticed it starting to happen. I tried reflashing and I'm still in the same boat. It's summertime, so i can't say this relates to cold temps.