[firebirdude]

Just bought my 13 SE about a month ago. Has 21k miles on it. Just wondering if this is normal...

When I start the car in the morning for the first time, it idles a little rough. Nothing crazy. But it's enough to shake your butt in the seat or cause ripples in a water bottle in the cup holder. It's like I'm sitting in a huge diesel F350. If you watch the RPM needle, it actually bounces a bit. Bounces up and down about 100RPM. Then when I shift into reverse.... it actually gets a little worse and starts flirting with dying.

Again, I want to stress that it's not really THAT bad... but it would be easily noticeable to anyone that even didn't drive the car on the daily. Like, "Hey, it shouldn't be that way." But then again, I felt the same way about the normal trans shifts while driving. But I read that it's pretty normal and I certainly don't have the rough "shuddering" that many describe, so I let it go and live with it. Just saying....the car is practically new and it idles like it's missing a cylinder.

Once the vehicle is warmed up, I really don't seem to notice it much anymore.

I'd just like some feedback before I make a big deal out of potentially nothing. The closest Ford dealer to me is ~1 hr. And if this only happens with a cold engine, they're probably gonna want me to leave it overnight. So it quickly becomes a PITA for me.

 

[morrjr]

I purchased a used 2013 SE hatchback in August, and I am experiencing the same behavior. I think it may be normal - Ford sets the idle low to increase gas mileage, and the low idle causes the car to run just a bit rough when cold. Mine smoothes out after the engine warms up a bit.

 

[CunFFS13]

Did you get any CEL on the dash?
Try using some "gas cleaner" or so

 

[firebirdude]

No CEL. If there was, then obviously I'd know something was up.[wrenchin]

 

[wizzells]

I'm inclined to say that it's normal. Bothered me a bit at first, since I came from 6 cylinder Toyota that was pretty much buttery smooth cold or warm.
Like yours, mine has a bit of an erratic idle as well until warm.
I test drove 3 others before buying the one I got and they were all similar.

 

[firebirdude]

Can anyone else see their RPM needle bounce around like that?

 

[TooOld]

Can anyone else see their RPM needle bounce around like that?

Not mine. Would suspect idle air control valve problem.

 

[sailor]

No IAC on these since they went to 'fly by wire" electronic throttle in '08. All the idle adjustments are made with the TB opening commands, same way it opens for acceleration.

 

[TooOld]

No IAC on these since they went to 'fly by wire" electronic throttle in '08. All the idle adjustments are made with the TB opening commands, same way it opens for acceleration.

So does it adjust idle speed via the throttle body plate position?

 

[BeastMD]

Mine is a little rough when i start in the morning and the ac is on. But it settles to smooth after a minute or 2.

 

[sailor]

So does it adjust idle speed via the throttle body plate position?

Yup, ever since '08 & introduction of the electronic TB.

'07 was the last year for cable operation of the throttle body & use of an IAC valve for idle adjustment.

 

[BeepBeep2]

Mine also runs very rough when cold. In the summer it's great, in the winter, the car definitely needs a minute to warm up before the idle settles down. When it's running great, there is only +- 20 RPM variance in measured idle speed, when it's feeling rough I get about 80 RPM variance and can visibly see the needle shaking up and down.

I don't think it's that much of an issue unless it starts happening all the time or getting worse.

 

[moshichiu]

GDI engine is different from traditional multi-port injection engine, there is a temperature drop of compressed air in the cylinder after fuel is injected into the cylinder due to absorb latent heat for evaporation, in addition, it's lean burn, the temperature of combustion is lower than traditional engine, quenching effect happens when flame kernel is reaching to surrounding metals. So carbon built up due to quenching in light load condition is much quicker than traditional engine! Rough idle will be one symptom of such carbon built up.
I use lowest octane gas available to improve the burning inside the cylinder, any additive can improve the speed of burning will help.
Change the spark plug to one range hotter, NGK 5 or Denso 16, I recommend ITV16 but the gap need to be adjusted to 9mm.