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Discussion Starter #1
Hey guys, I have a 2018 ecoboost automatic convertible with 11.2k miles on the car. I have noticed some weird stalling/hesitation when I start the car up and start driving at low RPM and low speed (~10mph). So it happened twice so far. The first time, I got home from work and put the car in the garage, about an hour and a half later I went to take the car to the store, turn the car on, pull it out of the garage (i drive in sport/spot+ mode most of the time), and lightly press on the accelerator pedal, as soon as I did this the engine felt like it was dying/surging/vibrating. I immediately limped it back to the garage and put it up on jack stands. I changed the spark plugs and poked around to see if the wheels had any play in them (they did not). So I took it down 2-3 days later and drove it for around 5 days without issue. Last night the same thing happened again, but not as violent as the first time. This is the first time I used a type of gas other than costco 93 octane. I put in Chevron 93 octane and put in royal purple max atomizer, do you think the car is freaking out because it has fuel that it isn't used to or is this some mechanical issue?

I do have mods on the car:

Airaid CAI
Steeda throttle body spacer
Mishimoto catch can
JMS PedalMAX throttle response enhancer
Mishimoto intercooler
Mishimoto Catted Downpipe
Flowmaster Y-pipe resonator delete
CVF charge pipes (hot and cold side)
Turbosmart BOV
Unleashed Tune

The problems seems to have started a week or so after the install of the mishimoto downpipe. I have no idea if it is related to it, but I do not see how it could be.

I have taken it to Ford and the issue (of course) did not present itself while it was there. I plan on cleaning the MAP sensor, cleaning the PCV hoses on the mishimoto catch can.

I already changed the spark plugs. Do you guys have any idea as to what may be causing this and where I should look to?
 

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You're not alone; I have a similar issue with my box-stock '18 M/T when it's cold (the engine). On occasion, when driving down the side road from home or leaving work (after it's sat for many hours), it acts as if the throttle snaps back and forth between "light acceleration" and "close". It doesn't run roughly or sound odd, but it does cause my head to rock back and forth. When it happens, it's only the first time coming up to speed (30 mph) after leaving its parking area.
I run top-tier 91 octane 10% fuel. Spark plug change didn't affect it. It's never been more than the initial drive-away, and doesn't happen all too often, so not enough to put me in motion to take it to the dealer. 'Never had a CEL.
Keep us posted if you learn anything more, as I'm very curious as to what might be causing these occurrences.

Nathan
 

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Discussion Starter #3
You're not alone; I have a similar issue with my box-stock '18 M/T when it's cold (the engine). On occasion, when driving down the side road from home or leaving work (after it's sat for many hours), it acts as if the throttle snaps back and forth between "light acceleration" and "close". It doesn't run roughly or sound odd, but it does cause my head to rock back and forth. When it happens, it's only the first time coming up to speed (30 mph) after leaving its parking area.
I run top-tier 91 octane 10% fuel. Spark plug change didn't affect it. It's never been more than the initial drive-away, and doesn't happen all too often, so not enough to put me in motion to take it to the dealer. 'Never had a CEL.
Keep us posted if you learn anything more, as I'm very curious as to what might be causing these occurrences.

Nathan
I'll let you know. It is driving me insane thinking about it since I get very meticulous with this sort of thing. I am going to figure it out and I will keep you posted on what helped me. Thanks for letting me know I am not completely alone in this though haha.
 

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Don't have an answer but just wanted to compliment you on an excellently written post. Lots of detail so that everyone has a good understanding of what you are experiencing, plus the listing of mods which are often left out.

In contrast, a recent post on another place I visit: "Umm. So my mustang 16' ecoboost is making noise whenever I turn my steering wheels :(. Currently at 37,000 miles."
 

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Discussion Starter #5
Don't have an answer but just wanted to compliment you on an excellently written post. Lots of detail so that everyone has a good understanding of what you are experiencing, plus the listing of mods which are often left out.

In contrast, a recent post on another place I visit: "Umm. So my mustang 16' ecoboost is making noise whenever I turn my steering wheels :(. Currently at 37,000 miles."
Thanks for noticing! I read a lot of these posts and try to contribute as much as I can. I just gave everyone all the information I would want if I was trying to help someone out!
 

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Most of the of the weird drivability issues that seem fuel related trace back to the low side fuel pressure sensor or the evap purge solenoid.
Either one of those can go screwy without setting off a check engine light or failing completely.

Adam of tune+ references them in this guide-
Frequently Asked Questions

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Most of the of the weird drivability issues that seem fuel related trace back to the low side fuel pressure sensor or the evap purge solenoid.
Either one of those can go screwy without setting off a check engine light or failing completely.

Adam of tune+ references them in this guide-
Frequently Asked Questions

Sent from my SM-G960W using Tapatalk
Without going out to look under the hood (busy lounging on the couch after a rough week) to compare them to the pictures at Adam's website, weren't the '18's upgraded already? Or, is that not a sure thing?
 

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Without going out to look under the hood (busy lounging on the couch after a rough week) to compare them to the pictures at Adam's website, weren't the '18's upgraded already? Or, is that not a sure thing?
The purge solenoid had an issue with a poorly designed check valve on the 2015/16 models, the design was revised for later models and incidents of failures reduced considerably but the occasional failure of the actual electrical solenoid is possible.

The low pressure fuel pump sensor with the -BA designation at the end persisted into the 2018 year (pictured below from my 2017) the replacement has a -B designation and a slightly different design (little hole machined into the body above the threads).




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The low pressure fuel pump sensor with the -BA designation at the end persisted into the 2018 year (pictured below from my 2017) the replacement has a -B designation and a slightly different design (little hole machined into the body above the threads).
Yep, checked mine this morning and it is a BA suffix. I think mine was built in May ‘18.

Is this something I should just change or wait and see if any symptoms show up?
 

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Also take off your pedalmax.. same issue on my 5th gen Camaro . caused to go into limp mode every now and then. After I took it off never had that problem again .might be the cause
 

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Yep, checked mine this morning and it is a BA suffix. I think mine was built in May ‘18.

Is this something I should just change or wait and see if any symptoms show up?
I'll second Elvis's recommendation to see if the pedal max is causing an issue.

The low side fuel pressure sensor should read around the 70 to 80 psi range under heavy throttle with 60psi being the minimum if your SCT device has the sensor available to monitor you can check it while driving, if you see it dipping below 60psi or reading way over 100psi the sensor may be faulty.

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I have only owned my factory stock '15 for 3 months now (47,000 miles) but I have noticed that on the first start of the day while driving out to the paved county road in front of my house I can feel what appears to be the engine surging or the automatic transmission "hunting" for the proper gear. Like yours it only happens at low speed and once I get on the paved road and accelerate I don't notice it any longer. I just attributed it to a "cold natured" engine but maybe there is an underlying cause for it..
 

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Discussion Starter #13
Mine happened both times on a warm engine right after startup. I could maybe forget about it if it was cold. I am still trying to figure the issue out. Thank you all for your contributions!
 

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Mine happened both times on a warm engine right after startup. I could maybe forget about it if it was cold. I am still trying to figure the issue out. Thank you all for your contributions!
Is it like this? Just took my 18 auto in today because of this. Said it's likely gunna be a transmission.
 

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No, thankfully it's not like that. Its fine shifting and everything. The only problem is if I am going and then brake for a stop light the rpm dips low and then comes back up, but initially it feels like it is going to die when it dips.
 

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No, thankfully it's not like that. Its fine shifting and everything. The only problem is if I am going and then brake for a stop light the rpm dips low and then comes back up, but initially it feels like it is going to die when it dips.

I have the exact same fucking problem (and mind you, sometimes the car turns off when it does that)....
FFS, took it several times to the dealership and no one could figure it out. Last time i went there, i forced them to change the low fuel pressure sensor, and i soon as i turned on my car the RPM did its little dance non stop. I told them to take a look at the problem live as it happened in front of them, and that i won't be driving that car unless they fixed this fucking issue.

After several days they called me to tell me that they didn't find any issue, but they updated the car's software and It worked for like 11 months and now this problem is reappearing again OUT OF FUCKING NOWHERE.... FUCKING HELL !!! IM GOING MAD!!!! HOW COME FORD CANNOT IDENTIFY AND FIX THIS ****!?!?!?!?

PS: I drive a stock Ecoboost 2016.
 

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the base idle needs to be raised. i don't know if ford can/will do that for you but a custom tuner will.
 

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Go ahead and replace the low side fuel pressure sensor now. It can destroy your engine in a worst case scenario.
 
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