I4 - car revs "high" and sudden "launching/sudden thursting" in low gear

[Ch0wd3r]

Wondering if anyone with I4 experienced this. My car is basically brand new and less than 200 miles. Not sure how best to describe it, but this happens occasionally when accelerating from stopped or in slow traffic (all in automatic mode and in tour). I'd press on the gas (lightly and not hard at all), and the car sometimes get into a high rev (from sound but not necessarily seeing high on tach), so then I'd let off the gas a quickly and then would press again, but only for car to thrust forward and jerks like it's about to launch, which then would cause me to hesitate to press further and try to let go and repeat, and then the "launching" would shoot me off again. All happens quickly so it shakes me like 3-4 times before I almost have to press full on brake and then re-engage. It's almost like when drive a manual and the jerking when you can't work the clutch correctly, but this is an automatic...

Anyone has experienced this or any idea? Thinking if I should stop at dealership, but at the same time can't guarantee that I can duplicate this issue there since it happens occasionally, but frequent enough where it's pretty annoying/concerning when happening (not to mention makes me look like someone that don't know how to drive a manual car in traffic ).

Thanks in advance!

 

[Beachbum]

I4 owner with about 5K on the clock. Not had this at all. I would recommend getting it to the dealer soonest. Sounds as though its something that could catch you out at any time.

 

[Andy H]

I agree, I’ve had my i4 for almost a year now and this has never happened. It sounds like it could be dangerous if it happened in traffic or mid corner. The only thing I can liken it to is my E90 M3 in Sport+ where the throttle was insanely sensitive - kind of off/on. But I’ve not experienced anything like it in the Emira. It’s always behaved in a predictable way.

 

[Porter]

Sounds like the clutches in the DCT are not engaging properly. Could be a defective gearbox. Get it to the dealer ASAP.

 

[Rainier]

Does this happen on warm or cold tires? In Tour the car seems to rapidly transition from calm cruising 'mode' to boy racer 'mode' if accelerating briskly from a stop and its not necessary to press too hard on the accelerator for this to happen. Wondering if you might be fighting anti wheel spin logic?

 

[Ch0wd3r]

Thank you all very much. Agree this feels concerning and may visit dealership. But at the same time this doesn't happen at all when up to speed (like over 10mph) and mostly only happens fully stopped or stop and go traffic. I also tend to find that I'm able to get through it if I accelerate through it (vs. having to let go of gas due to traffic). It also doesn't help the new brakes are super grippy at the moment, compounding the movement.

@Rainier - thanks for the suggestion. Do you have an i4 and experienced this sudden cruise to boy racer mode as well? It does sound fairly similar to what I'm expericiening. However I don't find any correlation between cold/warm tires since I've experienced it in various moment of a drive (beginning/during/towards the end).

 

[Rainier]

Thank you all very much. Agree this feels concerning and may visit dealership. But at the same time this doesn't happen at all when up to speed (like over 10mph) and mostly only happens fully stopped or stop and go traffic. I also tend to find that I'm able to get through it if I accelerate through it (vs. having to let go of gas due to traffic). It also doesn't help the new brakes are super grippy at the moment, compounding the movement.

@Rainier - thanks for the suggestion. Do you have an i4 and experienced this sudden cruise to boy racer mode as well? It does sound fairly similar to what I'm expericiening. However I don't find any correlation between cold/warm tires since I've experienced it in various moment of a drive (beginning/during/towards the end).

Hmm, I was just wondering if it was a traction or stability control issue, but your latest info doesn't sound like that. I have an I4 and have not experienced what you are describing. It will keep in lower gears if it thinks you want a sporty drive (even in tour) and calms down again to higher gears after a short time if you don't continue accelerating. If you are sure you are not being overly aggressive with the throttle and it only happens below 10mph likely something else...

Briskly leaving a traffic light can cause high rpms for longer than wanted sometimes.

 

[Wiz33]

Wondering if anyone with I4 experienced this. My car is basically brand new and less than 200 miles. Not sure how best to describe it, but this happens occasionally when accelerating from stopped or in slow traffic (all in automatic mode and in tour). I'd press on the gas (lightly and not hard at all), and the car sometimes get into a high rev (from sound but not necessarily seeing high on tach), so then I'd let off the gas a quickly and then would press again, but only for car to thrust forward and jerks like it's about to launch, which then would cause me to hesitate to press further and try to let go and repeat, and then the "launching" would shoot me off again. All happens quickly so it shakes me like 3-4 times before I almost have to press full on brake and then re-engage. It's almost like when drive a manual and the jerking when you can't work the clutch correctly, but this is an automatic...

Anyone has experienced this or any idea? Thinking if I should stop at dealership, but at the same time can't guarantee that I can duplicate this issue there since it happens occasionally, but frequent enough where it's pretty annoying/concerning when happening (not to mention makes me look like someone that don't know how to drive a manual car in traffic ).

Thanks in advance!

US owner 250 miles, Have not experience this. Do you have a dashcam? if you do, you can probably find the recording and show it to the service people.

 

[Ch0wd3r]

Hmm, I was just wondering if it was a traction or stability control issue, but your latest info doesn't sound like that. I have an I4 and have not experienced what you are describing. It will keep in lower gears if it thinks you want a sporty drive (even in tour) and calms down again to higher gears after a short time if you don't continue accelerating. If you are sure you are not being overly aggressive with the throttle and it only happens below 10mph likely something else...

Briskly leaving a traffic light can cause high rpms for longer than wanted sometimes.

I'm fairly certain I step pretty light, but I'll keep an eye out and see how things progress. Maybe it is just the high RPM that I need to adjust to. We'll see, and Thanks!

 

[gcmak]

I'm not experiencing your situation exactly but have come across a few odd situations over the past 700+ miles of driving my i4 during break-in, where also accelerating from a stop or from a very slow speed - city and stop and go - the car starts to bucking to and fro, just like someone who doesn't know how to properly engage the clutch in a manual, and then the car holds the revs fairly high before selecting 2nd. Same as you, Touring mode, full automatic, and light throttle. I usually have to fully let off the throttle because at that point I'm probably involuntarily jabbing the throttle with the car's jerky movements.

This is the most recent video. Unfortunately I was playing a podcast so the audio isn't as clear and no in cabin cam to show how my head is just bobbing. If you raise the volume you'll hear the engine load/revs go up and down a few cycles before I let off and resume as the revs continue to climb (past 4K rpm) before it goes into 2nd.

 

[Ch0wd3r]

I'm not experiencing your situation exactly but have come across a few odd situations over the past 700+ miles of driving my i4 during break-in, where also accelerating from a stop or from a very slow speed - city and stop and go - the car starts to bucking to and fro, just like someone who doesn't know how to properly engage the clutch in a manual, and then the car holds the revs fairly high before selecting 2nd. Same as you, Touring mode, full automatic, and light throttle. I usually have to fully let off the throttle because at that point I'm probably involuntarily jabbing the throttle with the car's jerky movements.

This is the most recent video. Unfortunately I was playing a podcast so the audio isn't as clear and no in cabin cam to show how my head is just bobbing. If you raise the volume you'll hear the engine load/revs go up and down a few cycles before I let off and resume as the revs continue to climb (past 4K rpm) before it goes into 2nd.

Hey! yes, i think this is it based on the sound, what you described, and your cars body movement in the video! My first few times are intense jerky movements since i didn’t know what to do. The subsequent times I learned to let off the throttle like you said. When you said this was during your during break-in, are you past that now and this has stopped? or has this continued to occur from time to time (and if so, any concerns, idea as to what is causing this or discussed with dealer?). thank you.

 

[Rayjoedef]

The DCT in both m2s I had would buck at low speeds like crazy....it was usually mitigated by a more consistent depression of the accelerator....tough weather in NE as I have a total of 6 miles on my I4 so no help there.

 

[Rainier]

Based on the video, is it possible this is driver induced due to hesitancy on the throttle?