Same exact symptom at me. However, I'm currently at 2400 miles and this issue hasn't reoccurred in about 3 to 4 weeks, when in the past it was basically everyday. Maybe it is a break in issue?
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Breakin would include lots of ECU learning in this case, which would encompass @Drex’s hypothesis I assume. This would make the most sense to me; I’ve tuned and detuned my RS which has the same 2.3L ecoboost (albeit with more boost, hp, and torque) and this feels similar to what some tunes experience at half throttle in the same rev range. The bronco symptom just seems more pronounced, probably because of the weight of the vehicle.
What do you think a possible resolution to this would be?
Well, with the RS, it seemed to be a tuning condition that some tuners were able to optimize out. These were half-throttle, middle of the rev range, throttle hesitations or "yo yo"ing that were not nearly as pronounced as what I've encountered on the Bronco, but possibly still related? Here's a link deep into some RS forum threads with COBB tuner datalogs and such:
https://www.focusrs.org/threads/inconsistent-throttle-and-power-delivery.119638/post-2236184
Interesting correlations between the RS issue and the Bronco issue:
- Only happens in lower gears, when RPMs climb faster
- Only seems to happen when throttle input is consistent
- Happens only when oil temp is cold; increasing temp but not fully warmed up
- Seems possibly ECU/tune related; possibly overboost conditions causing the ECU to reel back a bit, then overcompensate again as output dips below and spikes above target?
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Hmm someone else mentioned having the dealer re install the engine software. Do you think that could resolve the issue?
I feel like anything that causes the ECU to relearn could "fix" the issue -- I haven't seen many instances of this issue that continue long after the break in period. These ECUs are constantly learning from throttle input, clutch input, gear position, etc. to try and optimize for your driving style. If haven't ever reset a modern ECU, or uninstalled a tune (effectively resetting an ECU), it's quite a night and day experience. The engine will rev way higher than normal at idle, or even dip below normal RPMs and get close to stalling immediately after the ECU is reset before it has any learning baked in. It's very possible the ECU needs a few of these yo-yo events to happen before it learns to avoid that combination of inputs/outputs.
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Sounding like the software needs remapped. A reinstall wouldn't change this
Maybe an update is coming and the reason there was a sas mt delay until second year.
Oh, I see. Makes sense. Good call to that.
I've already addressed this to my sales rep, so I'm wondering what's the best way to address it to the service dept. Or, is it even worth addressing it to them now?
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I have no indication whether or not this should be or needs to be addressed with your service department -- I haven't talked to my dealer about this, and it hasn't occurred again since posting here about the two times it happened to me.
Ah, ok. Gotcha. This happened to me for the first time today in a month. Odd how random it occurs.
Just had another occurrence of this for the first time in a while.
Outside temp low 60’s
Coolant temp optimal
Engine temp just below optimal (140-150F)
1st gear, about 3,000 rpm
Was just depressing the clutch to shift into second when the rpm’s dropped a bit — slight lurch as a result, but I was already clutch in when I realized it and just held the clutch in for a second or two before going into second. Tried to reproduce it in first gear right afterwards to no avail.
I had driven to lunch maybe 50min or so before this, parked with vehicle off for that time, then started it back up and was the first time shifting into second on that startup so still in line with the working theory of an ECU tune/learning issue. Doesn’t seem serious, but does catch you off guard when it happens unexpectedly. Rest of the drive was uneventful.
Outside temp low 60’s
Coolant temp optimal
Engine temp just below optimal (140-150F)
1st gear, about 3,000 rpm
Was just depressing the clutch to shift into second when the rpm’s dropped a bit — slight lurch as a result, but I was already clutch in when I realized it and just held the clutch in for a second or two before going into second. Tried to reproduce it in first gear right afterwards to no avail.
I had driven to lunch maybe 50min or so before this, parked with vehicle off for that time, then started it back up and was the first time shifting into second on that startup so still in line with the working theory of an ECU tune/learning issue. Doesn’t seem serious, but does catch you off guard when it happens unexpectedly. Rest of the drive was uneventful.
Interesting. As stated before, same that occurs with me. Mine has been very random as well, lately. Typically once a week or every other and always on a vs start while engaging first gear.
I showed my salesmen this thread and told me to keep him informed.
That's about it for that...
Yeah, I don't think there's anything a service department can do unless it reproduces 100% of the time -- it may just be some odd boost condition where the ECU cuts fuel or purges boost when that combination of variables (whatever it may be) is met. I make sure to note my coolant and oil temp when it happens because I have a feeling this is a somewhat-warm-but-not-fully-optimal oil temp issue only. Air temp plays a crucial role in ECU tune/learning on these engines because temp and air pressure are used to calculate mass airflow -- the RS is the same way.
If the MAP sensors on these engines are easy to get to like they are on the RS, I may just try to clean them off a bit with some MAF sensor cleaner and see if that resolves it. A dirty MAP sensor would cause similar symptoms just much more consistently.
No life or death concerns at the moment, thankfully -- nothing yet that would make me think us 2.3L 7MT folks are in the same boat (or similar) as the 2.7L folks unfortunately are with their valves.
If the MAP sensors on these engines are easy to get to like they are on the RS, I may just try to clean them off a bit with some MAF sensor cleaner and see if that resolves it. A dirty MAP sensor would cause similar symptoms just much more consistently.
No life or death concerns at the moment, thankfully -- nothing yet that would make me think us 2.3L 7MT folks are in the same boat (or similar) as the 2.7L folks unfortunately are with their valves.
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