Rough idle/stalling after start up

[rpt50]

My 17 (has about 22k miles) seems to occasionally have a really rough idle and it will stall, and this seems to occur only after the initial start up. I can keep the engine running by revving in neutral, and it runs perfectly at engine speeds above idle. I have not noticed the issue when the engine is warm, but that may be just because I usually drive the car for fun and then put it away, so it seldom gets started when the engine is already warm.

I've run into similar issues with the idle air control valve on a couple of Ford trucks with manual transmissions that I have owned, so that's what I am thinking is going on here. Any other thoughts? BTW, the check engine light is not illuminated.

 

[TyphoonFiST]

My 17 (has about 22k miles) seems to occasionally have a really rough idle and it will stall, and this seems to occur only after the initial start up. I can keep the engine running by revving in neutral, and it runs perfectly at engine speeds above idle. I have not noticed the issue when the engine is warm, but that may be just because I usually drive the car for fun and then put it away, so it seldom gets started when the engine is already warm.

I've run into similar issues with the idle air control valve on a couple of Ford trucks with manual transmissions that I have owned, so that's what I am thinking is going on here. Any other thoughts? BTW, the check engine light is not illuminated.

Pull the plugs* may be due to short trip driving. Do you run stock or 1 step colder plugs? Here is a good Diagram to use to diagnose plugs also

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[TyphoonFiST]

Should also be using this or a good GDI injector cleaner* must be a GDI cleaner or its fruitless.

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[Ford ST]

The car doesn't have an idle control valve that is a thing of the past. Vehicles are now drive by wire throttle bodies no need for that extra stuff anymore.

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[Capri to ST]

Some cars have had an issue like you described that's related to a problem with the evaporative emissions system. That typically just happens after filling up the car with gas, especially if you top it up after the initial click when it's full, but I just thought I'd mention it because it's a similar symptom.

 

[LiLfieSTa]

My 15 would do the same thing but only after a fill up and the first 5 mins after leaving the station.

Changed plugs and it went away, but thats just me

 

[rpt50]

Pretty sure it's not plugs. Ha ha I race two stroke motorcycles so I'm really familiar with those kind of issues, and the car never gets used for short trips. It always gets fully warmed up.

That fill-up issues may be relevant however. I have not really paid much attention to any relationship between adding gas and the problem, but I will now. Thanks!

 

[LiLfieSTa]

Pretty sure it's not plugs. Ha ha I race two stroke motorcycles so I'm really familiar with those kind of issues, and the car never gets used for short trips. It always gets fully warmed up.

That fill-up issues may be relevant however. I have not really paid much attention to any relationship between adding gas and the problem, but I will now. Thanks!

i forgot to mention that i did add a tune to go with it immediately after swapping plugs.

But yea that fill up things was more of the problem i had.

 

[TyphoonFiST]

So your car occasionally wants/tries to die after you fill up?

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[Sprinkle_Star]

I'd check into the possibility of having a faulty purge valve

 

[ToastAutoX]

I've been reading through a bunch of similar threads (seriously, if you search these forums there's tons of them) as my car has developed this issue in the past year.

I did a bunch of work all at once (step-colder plugs, intake plumbing, tune) around when my issue started so of course now it's hard to pin one thing down.

I do notice w/ a specific octane tune (91 for me in Cali) that the car is VERY sensitive to bad gas. I filled up recently at a different station and immediately had the start happening worse than usual. I've got some octane booster coming in this week, curious to see if a little nudge to the fuel will cause the issue to improve.

From what I can tell reading these threads there may be two distinct issues: the post-fillup rough idle and the cold engine 'rev and then let it drop' sputter. Currently I experience both to different degrees, but it seems that some people expreience one and not the other.

 

[joesiris]

I've been reading through a bunch of similar threads (seriously, if you search these forums there's tons of them) as my car has developed this issue in the past year.

I did a bunch of work all at once (step-colder plugs, intake plumbing, tune) around when my issue started so of course now it's hard to pin one thing down.

I do notice w/ a specific octane tune (91 for me in Cali) that the car is VERY sensitive to bad gas. I filled up recently at a different station and immediately had the start happening worse than usual. I've got some octane booster coming in this week, curious to see if a little nudge to the fuel will cause the issue to improve.

From what I can tell reading these threads there may be two distinct issues: the post-fillup rough idle and the cold engine 'rev and then let it drop' sputter. Currently I experience both to different degrees, but it seems that some people expreience one and not the other.

i too experience both. i have read that letting the gas nozzle rest in for a bit after filling helps and it does sometimes (i never "top off") but recently i have had it stall on me in the afternoons after work. i always let it warm up a bit before driving off but i noticed it only does it on days where it is cool on the way to work and hot leaving (now that spring is here ish) Its super annoying, and only lasts for a few miles (just like after filling up) wish i could pin down exactly what is going on

 

[ToastAutoX]

Octane booster didn't help the 'rev and let it drop' sputter. My COBB intake came w/ new sections of evap harness which I installed, next step for me is going to check all of those fittings and make sure they're air-tight.

 

[TyphoonFiST]

How many of you have had the Purge solenoid replaced?

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[ToastAutoX]

How many of you have had the Purge solenoid replaced?

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I was worried that it was the same part that came w/ my COBB intake (seen here). However upon further inspection and staring at diagrams I think the evap purge valve (and it's associated hoses) are actually a different section. So that will probably be the next thing I try after checking out the COBB lines.

 

[joesiris]

have not replace the solenoid, if that was bad wouldn't it throw a code ( i have no check engine light on)

 

[ToastAutoX]

have not replace the solenoid, if that was bad wouldn't it throw a code ( i have no check engine light on)

All depends on how Ford's ECU monitors things and what would trigger a CEL. Right now I'm going purely off my own experience with the car after 3 years of ownership.

 

[TyphoonFiST]

Here is a good read through..Specifically post#16.I know he had codes set But it show you some of the same symptoms you guys are seeing*

https://www.fiestastforum.com/threa...6c-p0106-64-2f-p1060-64-2e-p00cf-62-6c.23044/

 

[ToastAutoX]

Another data point: since COVID started I'd been driving my FiST infrequently and for short trips. Decided on Sunday to give it the old Italian tune up. After about 30 mins, rev sputtering is noticably improved. I did a partial gas fillup and started: no rough idle. There's probably a new evap solenoid in my future but for now it would seem driving the shit out of it helps.

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[joesiris]

weird thing is i just recently moved and my commute went from 8minutes to like 25 but it didn't start sputtering till a couple weeks ago (other than after fill-ups) so while that is still kinda short it may not be that for me, typhoon mentioned purge solenoid so got me thinking and researching and i think ill try to replace that and see what happens, although i really do need to take her on a good long trip, i hear the devils whip NC is nice this time of year