JCW 2015 JCW Auto shutters/surging at steady speed

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Old Jun 16, 2019 | 02:33 PM
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2015 JCW Auto shutters/surging at steady speed

I have noticed in the past couple week that speeds above 65 mph if I am at a constant speed that my has a very slight shutter/surge (not sure what I should call it) about every 10-15 seconds. I first thought it was my accelerator control so I started putting cruise on and it kept happening. Anyone else have any issues like this?
 
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Old Jun 17, 2019 | 04:50 AM
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I have the same thing but happens around 70mph with cruise control. It was really annoying going across South Dakota and was getting horrible mpg because of it. I ended up taking it off of cruise control to get better mpg.
 
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Old Aug 8, 2019 | 02:24 PM
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mine does it sometimes too. especially constant throttle.
 
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Old Sep 4, 2019 | 03:13 PM
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Came here from @F56 Black Ops 's thread. It's really interesting.
I've had 2 F56 now, one manual and one auto, and haven't seen this. Though I am in Oregon and very very rarely get up past 65 sustained speed.
What mode are we all in when this happens?

I'd be curious to see what all the cars with this going on have in common, if anything.
 
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Old Sep 4, 2019 | 05:22 PM
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For me, it happens worse in Eco, less in Mid, and is barely noticeable in Sport. It happens both with and without cruise control on, usually when going 80MPH and uphill. On level surfaces, it is less apparent.

I am going to install the stock intake this weekend (i've got a cravenspeed) and see if that has something to do with it. Also check for vacuum leaks, change oil, and then finally install JB4 (cuz i should!) and monitor throttle with OBDII scanner.
 
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Old Sep 5, 2019 | 10:36 AM
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Originally Posted by F56 Black Ops
For me, it happens worse in Eco, less in Mid, and is barely noticeable in Sport. It happens both with and without cruise control on, usually when going 80MPH and uphill. On level surfaces, it is less apparent.

I am going to install the stock intake this weekend (i've got a cravenspeed) and see if that has something to do with it. Also check for vacuum leaks, change oil, and then finally install JB4 (cuz i should!) and monitor throttle with OBDII scanner.
Let me know how removing the CS intake affects it if at all! Two F56 with that intake with no issue, so it would be curious if it had an effect. Wracking my brain to think of what could be causing this.
 
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Old Sep 13, 2019 | 09:26 AM
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Just as an FYI, an oil change with 0W-40 didn't make this go away. Still there. Also, a JB4 install didn't change things (in this regard- the power is REALLY nice, especially the torque). The JB4 app monitoring doesn't show TPS, so i can't view if the throttle is twitchy or not, but I have noticed that ignition timing goes from 18 to 20 when it happens (I'm assuming that's -18deg to -20deg or 18 to 20 deg advance). That indicates to me that there is a load increase signal going on somewhere. It could be the throttle pedal itself is too sensitive or giving false readings, the ECU is reading the throttle pedal position as changing (noise in the system), the throttle body is sticking/releasing allowing more/less air in, or the e-wastegate is fluttering open and closed, pushing more/less air in. Now that i
think about it, it could also be a noisy MAP sensor and the ECU is compensating.

I should also note that different gas has no effect. I've used cheap gas, spensiv gas, all the same.

Man, too much to diagnose at once. I need better logs to get a hold on this...
 
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Old Sep 16, 2019 | 11:40 AM
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I just drove a 2020 F56 loaner with like, 3k on the odo. Wow yeah that's so very weird. Really bad going uphill, hardly noticeable otherwise. Any mode at all too.
 
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Old Dec 16, 2019 | 09:54 AM
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My 2016 JCW just started doing this yesterday. I did take off the air cleaner on the CAI to clean but that is the only think. happens at higher speeds only.
 
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Old Dec 26, 2019 | 12:58 PM
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so the dealer reset he ECU and the surging went away.
 
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Old Dec 26, 2019 | 04:42 PM
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Originally Posted by madmix
so the dealer reset he ecu and the surging went away.
ctrl + alt + del
 
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Old Dec 26, 2019 | 04:44 PM
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Originally Posted by Minnie.the.Moocher
ctrl + alt + del
yah something like that.
 
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Old Jun 18, 2020 | 12:36 AM
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Hi!

I have this problem since my engine was replaced and ECU reset. Does anybody know what else can cause this? Any chance there is different "versions" of the ECU software that can cause this? My car has been in the shop for almost 3 months now and they cant figure it out.
 
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Old May 5, 2025 | 03:23 PM
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Reviving this thread

Reviving this thread as I have the same problem. Car drives completely normal except for steady state throttle it starts to stutter/hesitate. I am having dealer try to re program the ecu tomorrow but if that doesn’t work not sure what else to do? If anyone has a solution that would be super helpful thanks! For reference I have a 2016 f56 that just recently had an ecu update and shuddering started after the update.
 
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