[JO3]

I replaced my exhaust side vanos solenoid due to limp modes, but it didn't help my rough idle.

[335i E92]

Done around 500 miles since the reset and it's still bad so looks like this is not the fix. Kinda at a loss, any other suggestions?

Had both vanos solenoids replaced yesterday also.

[AWD Addict]

Well sh!t

[BimmerPod]

Originally Posted by mj6234

I don't really have a rough idle, but under load at around 2500-3000 RPM it feels like I have a miss that happens. It is most noticable in the higher gears, especially when going uphill. I have 32K on the clock and am going to replace the plugs this weekend. I am completely stock. It really feels like 1 cylinder is missing, so I am hoping it is just a plug.

Any luck or resolution to your issue? I've been having this as well... and it wasn't plugs / ignition coils. Car is at dealer but they can't do much (and i don't blame them) unless there are any codes, but car hasn't thrown anything yet

[805beemer]

Originally Posted by BimmerPod

Any luck or resolution to your issue? I've been having this as well... and it wasn't plugs / ignition coils. Car is at dealer but they can't do much (and i don't blame them) unless there are any codes, but car hasn't thrown anything yet

have you had your valves cleaned?

[335i E92]

Bump...

Anyone got anywhere with this yet? Definatley not valves as I had a full head off decarb recently. Also disconeted the battery over night & reset ecu with the BT cable with no improvement to the rough idle.

Under load it's smoother after the ecu reset so not all bad!!

[AWD Addict]

I think mine's getting worse.

[benchen]

Originally Posted by 335i E92

Ok here's the situation... I have the rough idle exact same stumbling and rpm jumps up from 600rpm to 750rpm when the car is warm. I have spent the last 18 months trying to fix this issue that started imeediatley after changing the original plugs.

Firstly what we are all experience is NOT hardware related its 100% software. I've had 2 further sets of plugs, 6 injectors & 6 coils, full engine out and head off decarb over the last 18months an nothing has fixed the issue. This is 100% an adaptation issue.

Last week my local Indy brought a BMW main dealer master tech down to try to help the diagnosis. After listening to the symptoms and the fact that none of the above have fixed it along with the major clue that it happened straight after the plug change he has come up with what sounds like the fix.

I am booked in with him next week and was gonna start new thread to tell the masses but I'm that convinced it's going to fix he issue I'll spill the beans now and hopefully it'll be the end of this f@&king annoying rough Idle for good for us all!!

I've read every n54 rough idle post there is and have tried every adaptation available, even Mr5's BT cable reset which helped some didn't do shit for me.

However there is a reset that the master tech thinks is the fix. It's not available through the normal adaptation menu you have to actually cause a misfire on the engine by running it with a loose coil. As you will all know as bad as this rough idle is it's never thrown a code for any of us.

So basically by making the car throw a misfire code it will allow the tech to then run a misfire test module which will open up a menu that allows a particular stratification adaptation reset to be made. It's this adaptation that will allow the tech to change to stratisfied rather than harmoginous and fix this bull shit problem for good.

As I said im booked in next week and will start what I'm hoping will be a new thread to confirm the fix. In the mean time I would all ask to speak to your own master tech regarding the theory and get yourselves booked in.

I have the same trouble for a long time and without any code, but the trouble disappeared after my technician replaced a fuel pressure sensor.
Hope it useful for you.

[335i E92]

Originally Posted by benchen

I have the same trouble for a long time and without any code, but the trouble disappeared after my technician replaced a fuel pressure sensor.
Hope it useful for you.

Hi

Thanks for the suggestion but i already had my low pressure fuel sensor replaced 6 months ago and it didn't solve the issue.

Is that the same one you replaced?

[benchen]

Originally Posted by 335i E92

Hi

Thanks for the suggestion but i already had my low pressure fuel sensor replaced 6 months ago and it didn't solve the issue.

Is that the same one you replaced?

No, it's for high pressure fuel sensor.

[AWD Addict]

Interesting.

The hunt continues...

[335i E92]

Originally Posted by benchen

No, it's for high pressure fuel sensor.

Someone correct me if I'm wrong but I'm pretty sure the sensor for the hpfp is actually part of the pump itself and can't just be swapped out, you'd need to replace the whole thing.

Im pretty sure the only sensor thats fuel related and an easy replacement is the low pressure fuel sensor.

[pecophilly]

I have this same issue. Mainly at startup in the morning and it runs rough for about a mile of driving. Then at idle I get the RPM jumps sporadically.

My techs have replaced injectors/swapped coils/replaced coils and even cleaned out ALL of my valves. (which were pretty bad)

The car runs better after all of that but I still get the terrible stutter every morning as if the car isn't getting enough gas.

I'm dropping it off Friday (Dec 9th) and they are having a BMW engineer get involved.

I have a PROcede installed but haven't had it turned on in over a month to completely rule it out as being a cause.

I'll be sure to report back!

[boxim]

had it happen once seems like a common problem you should all write letters to BMW head office and ask them too look into it, i think its unfair that so many of you are wasting all that time and money trying to solve on your own.

[bv1]

Originally Posted by boxim

had it happen once seems like a common problem you should all write letters to BMW head office and ask them too look into it, i think its unfair that so many of you are wasting all that time and money trying to solve on your own.

+1

I've been dealing with the same issues. Thanks to the OP I have saved thousands of dollars as I was about to go down the same route replacing the injectors / coils and so forth.

My rough idle seems to have gotten better in the cold weather for whatever reason.

What I'm dealing with now is after a couple of minutes at idle the car forgets what rpm to idle at and creeps up to 800 or so without being prompted by a stumble.

Part of the crew.... never had a misfire or code but rough idle.

[stratos_335]

I had idle misfires even when I bought the car and was completely stock.

I replaced spark plugs and cylinder 4 coil at 24k km and all misfires disappeared.

When I used NLS a week ago misfires came back. I'll replace cylinder 5 and 6 coils tomorrow and get some feedback.

[AWD Addict]

Seems like a growing number of us out there. haven't had too much of an issue this week. It does seem to get worse in wet/humid weather. It's been cooler and dryer this week (save for yesterday), and I've had only minor hiccuping.

[pecophilly]

Originally Posted by AWD Addict

Seems like a growing number of us out there. haven't had too much of an issue this week. It does seem to get worse in wet/humid weather. It's been cooler and dryer this week (save for yesterday), and I've had only minor hiccuping.

Strange because my issue (See above) is much, much worse on cold morning days. Guess this thing really is all over the map.

Doesn't seem like there is going to be ONE magical fix for everyone's issue.

[pecophilly]

UPDATE: So I told yous I would let you know what fixed my issue.

ALL OF THIS WORK WAS DONE UNDER WARRANTY (even valve cleaning)

1st Visit: Coils swapped from cylinder to cylinder to attempt to isolate fault. Would return next day with SES light.

2nd Visit: Fault thought to be isolated to a coil. Coil swapped out with new coil. SES light back on 2 days later.

3rd Visit: Fault thought to be an injector. Injector was swapped out. SES light back on next day.

4th Visit: Had the valves blasted with walnut shells and another injector replaced. Car ran much better but still very noticeable shake, rough drive every morning.

5th Visit: ALL injectors replaced. Issue seems to be completely gone. On Day 4 now with no start-up issues, no rough idle, no rough acceleration. However, it has been VERY warm these past few mornings (55+ degrees) and my issues occurred when it was colder in the morning.

I'll keep yous posted if the issue comes back. If not, assume all is well!

Hope this helps someone...

[scottro]

I believe I have the issue as well. Can feel the car missing at idle, mostly when engine cold and starting it in the morning. However once the RPMs come up while driving no misses at all, and completely fine under load.

No SES light.

[maxipad96]

I have the same issue when the car is at a stop. You can feel a slight bump. Hasn't thrown a code yet and occurred about 2 weeks after I installed all new Bosch plugs and had an oil change.

[orionredwing]

My car started off with idle rough, and no misfire codes. Idle rough went away after engine warmed up.

After 1 year, my car now idles rough on cold start AND is guaranteed to throw a misfire code (cyl 2) after 10-20 secs.

Swapped coils, changed plugs, so only thing I didn't do was replace injectors.