• Sign Up! To view all forums and unlock additional cool features

    Welcome to the #1 Fiesta ST Forum and Fiesta ST community dedicated to Fiesta ST owners and enthusiasts. Register for an account, it's free and it's easy, so don't hesitate to join the Fiesta ST Forum today!


Erratic Idle, drops/stumbles, then returns to normal.

Messages
45
Likes
13
Location
Houston
#62
What exactly would leaving the nozzle in up to a full minute have anything to do with the stalling issue? I experience it too, but only if I sit and idle right after, if I get going to a steady speed and then come to a stop it never happens. I'm sure there will be some kind of a fix or TSB eventually.
Equalize in-tank pressure or something? Not sure how the vapor recovery system works. Maybe my car is unusual, but the 'one minute wait fix' is a reality for me. I do see the same thing as you ,though, that it stalls only if the engine is idling right after the fill up. Once I get moving, there is no issue.
 


C. love

Active member
Messages
546
Likes
84
Location
rapid city
#64
Sounds like an air leak to me. Have you tightened your intake air hose clamps?
It not a loose clamp, check this morning after you mentioned it. Its super intermittent when I say super its like maybe once a week. So infrequent in fact until it gets worse I wont even bother with it. I actually figured it was something with the tune
 


OP
Maxpowa
Messages
173
Likes
28
Location
LA
Thread Starter #65
Update:

Sorry for the long awaited update! Dealer replaced Evap. purge valve 2 weeks ago. I've filled up twice since then and have had no stumbling/stalling issues since. Everything was covered under warranty at no cost to me. Will re-post to this thread if the issue re-emerges. It took so long for them to get the part (they ordered the wrong part the first time; had to wait two more weeks for the correct one to come in) to arrive. They also were nice enough to replace the climate control sensor in the dash which was making a loud buzzing noise. Everything seems fine for now...finally.
 


Messages
69
Likes
18
Location
Glendale
#66
My car has also been doing this. I'm running a Cobb stage 1 tune with an RMM. I am almost certain the RMM is not involved with the issue and upon uninstalling the tune, the issue completely goes away. It has turned off on me once before as well at a light. I am almost certain it somehow is involved with the Cobb tune but don't want to remove the tune entirely so I have just been dealing with it.

It's consistent with only happening after filling up the tank. Once the tank drops to half or less the issue vanishes entirely. Once I fill up again, the issue returns.

Without the tune, no problem, and that's whether I leave the nozzle in or remove it almost immediately after filling up. I tipped off and spilled through the overflow only once when the car was brand new and never tipped off again. And I usually leave the nozzle in a few seconds before removing because I hate dripping.

Would love to find a solution to this. I find myself having to rev the engine a little whenever I come to a stop after filling up and the following couple days. Only 20k mi and I have really looked after the car to the best of my ability. I love this damn thing. Hope we get a clear fix soon.. seems to be difficult from the looks of this thread to pinpoint the most common cause as people are experiencing it in many different ways and at different times.


Sent from my iPhone using Tapatalk


Sent from my iPhone using Tapatalk
 


Messages
105
Likes
34
Location
Alexandria
#67
My car has also been doing this. I'm running a Cobb stage 1 tune with an RMM. I am almost certain the RMM is not involved with the issue and upon uninstalling the tune, the issue completely goes away. It has turned off on me once before as well at a light. I am almost certain it somehow is involved with the Cobb tune but don't want to remove the tune entirely so I have just been dealing with it.

It's consistent with only happening after filling up the tank. Once the tank drops to half or less the issue vanishes entirely. Once I fill up again, the issue returns.

Without the tune, no problem, and that's whether I leave the nozzle in or remove it almost immediately after filling up. I tipped off and spilled through the overflow only once when the car was brand new and never tipped off again. And I usually leave the nozzle in a few seconds before removing because I hate dripping.

Would love to find a solution to this. I find myself having to rev the engine a little whenever I come to a stop after filling up and the following couple days. Only 20k mi and I have really looked after the car to the best of my ability. I love this damn thing. Hope we get a clear fix soon.. seems to be difficult from the looks of this thread to pinpoint the most common cause as people are experiencing it in many different ways and at different times.


Sent from my iPhone using Tapatalk


Sent from my iPhone using Tapatalk
This is a fairly common issue. Lots of people get the stumbling idle after fill up. It's something to do with the evap system. Your dealership should be able to fix it relatively easy, assuming they correctly diagnose it. Some people find that leaving the hose in for a while after it fills up helps, as does not topping off the tank.

Sent from my Pixel using Tapatalk
 


Messages
6
Likes
2
Location
Saint Augustine
#68
I've had similar issues. I only have 550 miles on my FiST. First time I filled it up I was idling by the pump while texting my wife that I was on the way home and my engine just shut off on me. The second time was again after filling up and it didnt shut off but it idled erratically for about 15 seconds and then smoothed out. I just figured the first time was because the dealership put regular in the tank and I put 93 for the first time. I did top it off about 13 cents, so maybe I will not do that and see how it runs. It's only done that both times I out gas in the tank.
 


Messages
8
Likes
1
Location
Casper
#69
New to this forum and my fiesta st. It's a 2017 with 1k miles. And so far I've had a couple issues. My transmission made an awful whine at about 500 miles, they replaced the output shaft, but at the same time that happened, I started having a weird problem with the idle. And it's not related to filling up. Whenever I'm going and push in the clutch coming to a stop the rpms drop to 500 and then it catches itself and returns to normal. No engine codes so the dealer has no idea how to fix it, they also checked for leaks and they can't find any. They told me to just drive it until something happens. So am I just expected to live with my brand new car having issues. Anyone have any idea so maybe I can clue them in ?
 


Messages
277
Likes
106
Location
Camden
#70
It has to do with how the evap system operates.

I had the same problems and chased it down looking for vacuum leaks cleaning the Throttle body, the Idle Air control and the pcv system. I fixed the issue when I changed the lines and canister for the evap system. So far the issue has not returned but I think it has to do with the check valve on the evap system.

My issue was not only after filling up but also randomly in traffic and it eventually got so bad the car would shut off unless I pushed the gas pedal or placed my foot on the clutch to raise the rpms. Made no difference if I was tuned or on factory tune.


"I've been told that if I make one more offensive remark, anywhere, at anytime I will be sacked. Even the Angel Gabriel would struggle with that hanging over his head." ~ Jeremy Clarkson
 


Messages
8
Likes
1
Location
Casper
#71
Thanks for the fast reply, I'm going to talk to them again on Tuesday to see if they will look into the Evap system. I just want my car to be running normally. I've barely had it a month and a half. And most of it has been spent in the shop. Seriously wondering if mines a lemon
 


HardBoiledEgg

1000 Post Club
Messages
1,076
Likes
516
Location
Fontana
#72
Omg my idle is insane. It used to be after fill ups but today it started doing it at every single light. Ugh
 


OP
Maxpowa
Messages
173
Likes
28
Location
LA
Thread Starter #73
Definitely bring it in for inspection of the EVAP system. I ignored the stumbling after fillups for a while, then the car started to idle terrible all the time.
 


HardBoiledEgg

1000 Post Club
Messages
1,076
Likes
516
Location
Fontana
#74
I use my car for work so can not afford to leave it at a dealer for a week to say it's fine


Searching online for a fix still
 


Zissou

Active member
Messages
540
Likes
137
Location
Charlottesville
#75
I use my car for work so can not afford to leave it at a dealer for a week to say it's fine


Searching online for a fix still
Tell them to do it in a day and use their shuttle. Or make them give you a loaner if your dealership will do that.

I miss owning a Mini Cooper, back when I would drove it off for service and they would ask me which loaner I would like to take.
 


Messages
38
Likes
5
Location
Charlotte
#76
Update:

Sorry for the long awaited update! Dealer replaced Evap. purge valve 2 weeks ago. I've filled up twice since then and have had no stumbling/stalling issues since. Everything was covered under warranty at no cost to me. Will re-post to this thread if the issue re-emerges. It took so long for them to get the part (they ordered the wrong part the first time; had to wait two more weeks for the correct one to come in) to arrive. They also were nice enough to replace the climate control sensor in the dash which was making a loud buzzing noise. Everything seems fine for now...finally.
Did you have any other mods at the time of getting the repairs made? and do you happen to have a part number for the purge valve they replaced? I need to do an oil change so I will take it in to Ford and see if they can look at the idle issue while the car is in for service. I could swap back to the stock RMM if it might be easier for Ford not to place the blame on the RMM, which doesn't seem to be the cause of the RPMs dropping.

I am getting this idle issue at different times, not just after filling up. The issue is more noticeable now with the RMM installed but the car has never shut off on me. RPMs usually drop near 500 but never below that.
 


LaserWhisperer

Active member
Messages
562
Likes
201
Location
Portland
#77
Tell them to do it in a day and use their shuttle. Or make them give you a loaner if your dealership will do that.

I miss owning a Mini Cooper, back when I would drove it off for service and they would ask me which loaner I would like to take.
Truth, I worked for a MINI / BMW dealership in Ohio. They really took care of their customers when it was needed to leave the car for an extended period.
 


Messages
29
Likes
9
Location
Suffolk
#79
Seeing the same issue on my 19. Started after first fill up.

Anyone got a part number for this purge valve yet?
Or just get it from Rock Auto?

Sent from my SM-N910V using Tapatalk
 




Top