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Discussion Starter · #1 ·
Strange problem with my 2016 Ecoboost that just started about 6 months ago. Only when at highway speeds and at about 4500 RPM, I'll get either a hesitation and then a surge, or a series of hesitations, slightly similar to the rev limiter kicking in. Sitting in neutral, or at street speeds this never happens. And no error codes are being thrown when it happens. As long as I stay below that threshold everything runs fine but I have lost quite a bit of gas mileage. It had lost some performance but the plugs and coils brought that back quite nicely. I also change the synthetic oil every 5000 miles. I do not see any loose hoses. No hissing or pressure loss sounds when running. Almost impossible to diagnose since it never happens when sitting still, even all the way to red line, and held for any period of time.

I've repeatedly checked for codes using the SCT X4 tuner, which I normally leave connected for telemetry. I have a 93 octane tune pushed that I've been using since February of 2017, Airaid CIA, Corsa 3 inch catted down pipe and Mishimoto cat back exhaust. Go fast bits by-pass valve mod, and Mishimoto oil catch can. All parts have been installed since the tune was pushed to the ECU.

Have had a full intake flush and clean done. New plugs installed, Denso one step cooler, Accel coils installed all this week. So far no change to the symptoms from any of these efforts.

No one with whom I've spoken has any idea what to look at, or replace next. Again, no error codes ever being thrown. All mods were done between November of 2016 and February of 2017 and everything ran fine until about 6 months ago. Oh and I am at 78k miles.

Ideas? Any other data that might help with ideas, certainly let me know.

Thanks in advance...
 

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Could be fuel pump related or dirty injectors.
When it comes to coils... Best to only use OEM.
But it sounds like its fuel related.... Running too lean due to lack of fuel.
 
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Have you tried going back to the stock tune to see if it still does it? Sounds like something in the tune to me
 

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Can your tuner also work as a data logger?
If so, you may want to record and analysis your car's performance a few times...
 

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Discussion Starter · #7 ·
Could be fuel pump related or dirty injectors.
When it comes to coils... Best to only use OEM.
But it sounds like its fuel related.... Running too lean due to lack of fuel.
How would one go about isolating injectors versus fuel pump? Not like I really want to just replace either item due to cost, and then hope it fixes the problem..
 

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Discussion Starter · #9 ·
Have you tried going back to the stock tune to see if it still does it? Sounds like something in the tune to me
I went to restore the stock tune and the tuner crashed. I had to send it in to be repaired. But it should be noted that this tune ran fine in the car for four years, without any issues at all.
 

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Discussion Starter · #11 ·
I put 1200 highway miles on the car yesterday, but due to about 1000 of that being in wet to torrential rain conditions didn't really hvae much opportunity to push the revs very high. I did get to or go slightly over 5k a couple of times. And the symptom never manifested. I should add at this point the coils were brand new and the car had only been driver a few miles between the coil install and yesterday road trip.

And thanks for all the ideas, everyone. Greatly appreciated. Keep them coming.
 

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Discussion Starter · #13 ·
Is this happening under acceleration or while statically holding rpm?
On acceleration, and only at highway speed. Not at lower speeds, nor as far as I can tell in first or second gear. But sometimes when it occurs it will continue to do it until I come off the throttle. Never happens when sitting still, even at steady throttle and past 6000.
 

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It could potentially be a wastegate issue dumping exhaust gasses when it shouldn't be at higher RPM and acceleration. Tune+ has a dyno showing how the factory wastegate can do do this during a dyno run. Mine will dump around 4k -5.5k and feels like a on off surge like power is being cut and then turned back on. I can see the boost gage dipping and popping back up. But this normally only happens while accelerating but not WoT. And doesn't happen all the time. When i finally pro tune i will replace the wastegate for this exact reason.
 

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I had something similar mainly in 3 and 4th gear when cruising. My positive correction was 10plus. A reflash bought it down to positive 4 and it solved it.
 

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Discussion Starter · #16 ·
I had something similar mainly in 3 and 4th gear when cruising. My positive correction was 10plus. A reflash bought it down to positive 4 and it solved it.
Your symptoms sounds very similar for sure. I had to send the tuner back to SCT because it wouldn't push tunes, nor would it accept udates, even after many hours on the phone with their support. So when I get it back I will definitely be trying to reset it to factory and then repushing the custom tune I use.
 

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Discussion Starter · #17 ·
Problem still manifesting, but now it seems to not happen until I get to or a little over 6000 RPM. around 5500 so far it is fine. Tuner should be back tomorrow so I can then try pushing some different tunes to see what happens. I did not see any dip in the boost gauge on the dash, but let's be real that Boost gauge that comes with the Performance Pack is pretty crap. But with the tuner back I can get far more accurate telemetry.
 

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Strange problem with my 2016 Ecoboost that just started about 6 months ago. Only when at highway speeds and at about 4500 RPM, I'll get either a hesitation and then a surge, or a series of hesitations, slightly similar to the rev limiter kicking in. Sitting in neutral, or at street speeds this never happens. And no error codes are being thrown when it happens. As long as I stay below that threshold everything runs fine but I have lost quite a bit of gas mileage. It had lost some performance but the plugs and coils brought that back quite nicely. I also change the synthetic oil every 5000 miles. I do not see any loose hoses. No hissing or pressure loss sounds when running. Almost impossible to diagnose since it never happens when sitting still, even all the way to red line, and held for any period of time.

I've repeatedly checked for codes using the SCT X4 tuner, which I normally leave connected for telemetry. I have a 93 octane tune pushed that I've been using since February of 2017, Airaid CIA, Corsa 3 inch catted down pipe and Mishimoto cat back exhaust. Go fast bits by-pass valve mod, and Mishimoto oil catch can. All parts have been installed since the tune was pushed to the ECU.

Have had a full intake flush and clean done. New plugs installed, Denso one step cooler, Accel coils installed all this week. So far no change to the symptoms from any of these efforts.

No one with whom I've spoken has any idea what to look at, or replace next. Again, no error codes ever being thrown. All mods were done between November of 2016 and February of 2017 and everything ran fine until about 6 months ago. Oh and I am at 78k miles.

Ideas? Any other data that might help with ideas, certainly let me know.

Thanks in advance...
I have the same issue, I think. I drive 2017 eco with Performance Package. I usually only get this issue when I'm heavy on the gas. No codes, i replaced spark plugs at 50k when i started with this issue.
 

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Discussion Starter · #19 ·
II usually only get this issue when I'm heavy on the gas. No codes
Precisely what I see. Only when full throttle, with or without normal, sport or track mode selected. New plugs, new coils, intake cleaning, problem now happens at a higher RPM, but is not gone. Pushed a new tune and still no difference.
 

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I does record data, but I have no idea what I would be looking for. Ideas, suggestions welcome.
Air to fuel ratio, since it happens when you're moving and not sitting still. An example is your Intake Air Temperature will change when you're moving vs sitting still and the ECU will make adjustments accordingly. Compare your data log sitting still vs moving at the same RPM.
 
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