[OpusTpa]

I bought a 2018 M240i convertible back in March and it’s a wonderful car. There has been one issue that has lingered and I’m not sure if it’s a fault or a trait. The car stumbles a bit in low rpms around town. It’s a bit reminiscent of the old supercharged Mini Cooper S issues when they first came out.

The car definitely is not lacking for power; and on the highway, it’s fine. Never having driven the model before I wasn’t sure which is which so I took it to a dealer as it was still under warranty. The technician felt it on the drive, but wasn’t able to achieve a fix. After trying a few days, they reprogrammed it and turned it back to me with a message from BMW that said “if programming does not fix it, it is normal operation.” They also reported driving another vehicle with the same engine doing the same thing. Based on the fact that I had it on the drive home and still do, I assume it’s “normal operation.”

Any thoughts or experiences on the matter would be greatly appreciated. I’m definitely content to live with it hoping it doesn’t point to another, costlier fix down the road.

[JD11937]

I've experienced this on my car and wasn't clear if it was the engine or the transmission doing it. I have almost 60,000 miles on my car with no issues so I've resigned it to a normal quirk of the car.

[PeterWT]

The same w/ OE tune, Dinan piggybacks and MHD stg1 & 2 flash tunes w/ OE DP and CTS cat DP.
It seems to happen less if you keep the RPMs up by keeping the transmission in "Sport"; however it still sometimes happens anyway at lower RPMs.
It's a "feature".

[OpusTpa]

Originally Posted by PeterWT

The same w/ OE tune, Dinan piggybacks and MHD stg1 & 2 flash tunes w/ OE DP and CTS cat DP.
It seems to happen less if you keep the RPMs up by keeping the transmission in "Sport"; however it still sometimes happens anyway at lower RPMs.
It's a "feature".

Thanks for the replies. That's very helpful and reassuring. I ran into someone with a 2018 M3 and he said the same thing. We've both had our cars about the same period of time. To your point, I've found if I basically drive like a pissed off teenager, it doesn't do it.

Still love the Bavarian response, "if it continues, it's normal operation."

[Mjolnir12]

Is this a manual or auto? By stumble do you mean it just doesn't have low end torque, or is it more of a "lugging" at very low RPM? My manual M240i does that, but so does every other manual car I have had (this is at very low RPM, like around idle or below). I haven't noticed anything else at low RPM other than a bit less torque, but I live at high elevation so there is a bit more turbo lag and it takes a second or so for the boost to build up to the point where it actually starts hauling. Compared to an N55 at sea level it actually feels like less torque until the turbo kicks in and it turns into a rocket ship.

[OpusTpa]

Originally Posted by Mjolnir12

Is this a manual or auto? By stumble do you mean it just doesn't have low end torque, or is it more of a "lugging" at very low RPM? My manual M240i does that, but so does every other manual car I have had (this is at very low RPM, like around idle or below). I haven't noticed anything else at low RPM other than a bit less torque, but I live at high elevation so there is a bit more turbo lag and it takes a second or so for the boost to build up to the point where it actually starts hauling. Compared to an N55 at sea level it actually feels like less torque until the turbo kicks in and it turns into a rocket ship.

This is an automatic. I’d say it’s more of a lugging, a hesitation and it’s probably around 1500 usually. If you keep giving it the beans, it’s fine. I’ve been doing that more and it’s doing it far less and is also a blast. Just need to get used to 15 mpg and hope I don’t get pulled over. I’m basically at sea level.

[Mjolnir12]

That still sounds like something is wrong though. Is the idle rough ever?

[OpusTpa]

Originally Posted by Mjolnir12

That still sounds like something is wrong though. Is the idle rough ever?

Not that I‘ve noticed. It’s aggressive when starting then calms down and it’s fine.

[MarcoZandrini]

You should scan the engine computer (DME) and the transmission computer (EGS) for codes. The Service Engine Soon light is on only when an emissions-related code is present.

[OpusTpa]

They had the car for three days did a total evaluation with a reprogramming and it was the same.

[JD11937]

I've thought about this a little more. It has happened to me when the car is cold and I go directly to manual mode. I have noticed in full auto that the car will hold the first one or two gears and not shift until a little higher in the rev range. I tend to drive in manual mode and ever since mimicking this behavior it hasn't happened.

Obviously all speculation at this point but the thread got me thinking about it.

[Finn Germai-Yaz]

unplug the battery for a few minutes and plug it back in. maybe needs a reset

[MassNerd]

When the transmission is in auto mode and doing a quick stop and go or going very slow, I experience what you might call at "stumble". It's the transmission in my case. If I put the transmission in manual mode, it doesn't happen. I get instant power all the time.

The programming on this ZF8 is excellent, most the time, but this is one thing that bugs me. I drive in manual mode most the time so it doesn't bother me much.

[PeterWT]

Originally Posted by MassNerd

When the transmission is in auto mode and doing a quick stop and go or going very slow, I experience what you might call at "stumble". It's the transmission in my case. If I put the transmission in manual mode, it doesn't happen. I get instant power all the time.

The programming on this ZF8 is excellent, most the time, but this is one thing that bugs me. I drive in manual mode most the time so it doesn't bother me much.

This is a good explanation of what I experience as well. As I stated above (not so eloquently) this is unfortunately characteristic behavior for the B58/ZF8.

[figuec56]

So I am having a similar issue. It started within the last 3 months. When trying drive slowly (around a parking lot) especially from a dead stop the car will stumble almost stop and drop about 300 rpm and come right back. Also when trying to slightly accelerate and rpm is just over 1000 the car surge then go back to normal. It will repeat that till I either give it more gas or take my foot off the gas. Car sounds fine at idle. And no issues if I'm in sport mode as RPM are usually 1500 or higher. Any thoughts. I thinking of running fuel system cleaner to see if that helps.

My car is a 2017 with 60k miles. I have kept stock and had BMW replace spark plugs back in March.

[mevans313]

I know everyone else has already piped in, but yes. Concerned me too at first but at low speeds and low RPMs the car is not very happy. I just deal with it!

[laskoir]

Same problem here. M240i 2017. Will get BMW to check it out as still under warranty but don't expect them to find anything.