this happens to my car but i have never stalled from it. i have a feeling its a problem with the injectors. i usually notice this happen more when it gets above a certain ambient temp or when my fuel is low.

 

Definitely tune related.
What mods you running?
Intake?

 

seeing as i dont have a tune, and im sure others that have this issue dont have tunes as well, that doesnt seem to be the case

 

I have come across a few with this type of symptom including myself, and we've all chased it a bit with varying success.

Have you thrown any lean codes, stuck lean?

LTFT all over the place, yes.
Other than idle though runs well?
Occurs regardless of tune...yes?

Tried leak testing good.
Check exhaust leaks good
Front 02, biatch to do....nope

I've heard guys trying the fuel filter, didn't seem to do it....

For me, and a few I have communicated with, it was the fuel pressure sensor, way easier than the 02 sensor, and cheap.

A few others I know this dind't work and they are now going after HPFP and injectors....

 

Do you have the pressure sensor part number?

 

Hey Crevarius - saw you might have sorted yours?
https://www.focusrs.org/forum/154-f...eshooting/112086-p0171-p2195-bank-1-lean-sensor-signal-biased-stuck-lean-2.html
How would you have described your cars behavior prior? And for the mechanical noobs, where is this sensor, something I could easily take off and WD? Any change of a pic? haha tia

 

Hey Crevarius - saw you might have sorted yours?
P0171 and P2195 Bank 1 Lean/Sensor signal biased/stuck lean
How would you have described your cars behavior prior? And for the mechanical noobs, where is this sensor, something I could easily take off and WD? Any change of a pic? haha tia

This started small and turned into a wall of text. Sorry!

The symptoms were:

• Lean codes (P0171 / P2195)
• Stumble and hesitation under partial throttle
• Terrible gas mileage
• Hunting idle that sometimes caused the car to stall. The hunting idle would go between 400 and 750rpm.
• STFT (short term fuel trim) was all over the place, going between +25 and +50
• LTFT (long term fuel trim) would eventually settle in around +20
• AFR Actual was reading lean, between 15.6 - 19.4
• CMS (catalyst monitor sensor, or rear narrowband o2 - EGO on your AP) was reading 1.65v indicating extreme rich conditions

The sensor is right at the front of the engine, just behind the intake manifold. I got mine here:
Sensor - Fuel Injector Pressur - Ford (CM-5233-) | Eastgate Ford Parts CA
edit For our friends in the UK, part number is 5 255 376. (thanks @Jgray2016)

Tools required:
1 1/16" deep socket
WD-40
Rag / lint free cloth
Eye protection

1. Wait for the engine to be cold
2. Disconnect the low pressure fuel pumps, located under the rear passenger seat. Flip up the seat bottom, pull the red tabs and disconnect both wiring harnesses.
3. Start the engine and wait for the car to stall. Wait 2 minutes then do it again. Do this 3-5 times.
4. Disconnect the positive battery cable
5. Disconnect the FRP sensor harness
6. Place a shop rag or towel underneath the FRP sensor
7. Using a 1 1/16" deep socket, remove the FRP sensor (make sure to wear eye protection, and catch leaking fuel with the rag/towel)
8. Lubricate the FRP sensor's mating end with WD-40 or similar silicone free solvent/lubricant
9. Reverse the procedure to re-install. Torque to*24*lb.ft*(33*Nm) Do not overtorque this as you can deform the mating flange.

Good luck with your fix!

 

Might be worth checking/replacing the PCV valve.

Ciao

 

p2195 was stored according to ford
fuel system was pressure tested by ford
full leak down test done by my mechanic
o2 replaced by mechanic
i've tried new plugs, new vac lines, all kinds of stuff

it's doing a number on me haha

 

I've got this exact same issue. Usually when it happens my fuel trims start going all over the place, usually up to a combined ST+LT Fuel Trim of +50% to +75%. The car also lurches real bad a low load and low RPM cruising when this happens. Looking at the logs it's hard to tell exactly what's going on, since the conditions before and during the idle dip/stumble aren't consistent. In some cases it looks like my HPFP is dropping a lot, but in other cases it looks like it's just fine.

Have you got yours figured out?

 

Nope not yet ?
It has actually been ok for a while and just this morning started up again

 

So this confirmed to be attributed to a bad sensor? Thanks for the walk through but did it fix the actual issue?

I have this on my 2018... Subtle throttle input and car feels like it's about to stall taking off in first gear, does a rpm dip then catches up and works fine from there.

 

It fixed my issue. YMMV.

 

I had the same exact issue and my dealership is saying its a failed fuel injector. I get my car back Wednesday so hopefully this fixes the issue for me!
Good luck to you!

 

Checking in, about 2 months / almost 3k miles later and I have had no issues since replacing the HPFR sensor.

I had actually bought the EVAP Purge Valve, WBO2 Sensor, and the HPFR Sensor. Replaced the EVAP first, didn't do anything, then replaced the HPFR sensor and have had no issues. Which I'm happy with because that WBO2 sensor looks like a PITA to get to.

 

Any idea how to get the clips off on the fuel pumps? I pulled the red clips and am unable to get it to wiggle out... The shop manual wasn't clear either... Any advice?

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Anyone? Seriously can't get these off lol

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I actually had this happening while on my way to ViR Oct 3rd. Was in traffic in Hillsborough, NC and going down hill in gear for engine braking the car was just popping. The last time, and first time, it did this was just after fueling up while in the mountains during the ecoboost takeover at the dragon and only did it briefly after the refuel stop (my car has idle issues after refuel has ever since the recall). While idling at lights car was stumbling and then picking back up. Intake temps were 130-140 and when the car would stumble I would see AFR at about 10-11:1, then it as the idle would catch and go back up it would swing to 16-19:1 then settle in on about 14.9:1 until the stumble would repeat. It was hot that day. This car has never been tuned.

 

Let me know what you find. I’ve been still dealing with this


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Still need help taking off the connections on the fuel pumps... They won't come off at all. What am I doing wrong?

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go to the 3:00 mark

 

Hi All,

I swapped the fuel pressure sensor today and I'll report back if it helps with the rough idle.

Unfortunately I broke the yellow retaining tab of the connector that goes into sensor. Does anyone know what the connector part number is, or even better the specific tab that goes into the connector?

For now I have the connector duct taped to the sensor housing but I want to get it replaced before too long.

 

The evap valve on the pipe under the hood that goes from behind the hpfp across the top of the intake manifold and into the side port of the intake manifold on the left hand side while looking at the engine bay from the front.

I wonder if we should just plug that port once and for all.

 

There's a reason people persevere with them, nothing stock handles anywhere near as well on a track or a twisty road.