My 11 FX4 5.0 just did this on startup for the first time yesterday morning. Started truck up after sitting all night, immediately noticed a miss and roughness to the usually super smooth idle. Only idled 10 seconds or so and I revved it lightly as if to clear it out (habit from running a lot of big cammed engines in musclecars I guess) and it smoothed right out and never did it again. Glad I read through this thread. May talk to the tech and just hand him this thread printed out and see what he thinks. A lot of good info on here.

 

Was the ambient temperature or humidity vastly different last night when you shut it down, compared to this morning when you started it up again? The engine control system could have been "remembering" that fuel mixture setting and took a bit of time to re-compute a new mix, once it "saw" what the exhaust O2 sensor was saying, more in keeing with the changed outside air conditions at the re-start - at least that sounds plausible to me...

 

It's a timing issue, not fuel related.

Yup they all do it; it's just that people don't notice it.

Glad this thread helped you out. You could hand the tech all the data in the world supporting it's a timing issue and he'd probably sit there and deny it. Can't stand Ford's service.

 

Whatever...

 

...?

Didn't you see the video I posted at start-up of it running -9 deg of ign timing but the whole time AFR's were constant and then as soon as timing trimmed out it quit running rough...?

 

Yes, I saw the video - thanks!

 

I have the exact same issue. Bucks and jerks when I start it cold and then try and drive away. The problem totally goes away if I let it idle for 30 seconds or so.

 

My build date was in May of this year. Only have 2300 miles on it now. Mine does it as well. I just let it idle back out of the drive way go to the end of the road and it's good to go. Just a bit of hesitation and rough idle for about 20 seconds.

 

Mine has done this some also if you try to drive off without letting it warm up for a couple off minutes. Is ford retarding the timing for a specific reason on the cold start?

 

i just bought my 12 xlt, i noticed this morning it does this as well. My truck only has 180 miles on it. What gives?

 

Mine has done it for some time now, and has been in the shop 3 times. They claim (like so many of the other issues wrong with my truck) that they cant re-create it.

My issues:

1 - knock/internal noises in the motor, especially after towing it, then letting it idle. I can re-create this problem easily, dealer says they cant.
2 - vibrates bad @ speeds over 50mph when towing my 4500lb boat (now vibrates when not towing/hauling also due to it wearing out drive train components). Dealer has admitted there is a problem with the truck but says there is no fix and I have to live with it as a characteristic of the truck, even though it will ruin my drive train and shorten its lifespan.
3 - cab was installed ½" out of square from the factory and not lined up with the bed. Dealer actually fixed this.
4 - steering locks, then jerks free while driving like p/s motor is locking up. I can re-create this problem easily (and 3 others who have driven my truck can also) dealer says they cant.
5 - wearing the front tires on the inside from the traditional Ford "front end sag". This started at less than 10K miles. Dealer refused to do anything (like line the front end) without me paying for the alignment.
6 - clicking noise in the front end, when the rear end loses traction and slips just a little.... like a hub is half engaged. I can re-create this problem easily, dealer says they cant.
7 - wind whistling into the cab. I believe it is through the vent/blend door under the dash (see issue #12). Dealer said first time in shop it was my hood protector. I removed hood protector, still whistled. Third time in shop they said the windshield wasnt sealed right and that was the problem. Really? Then why wasnt this fixed the first time, rather than lying and saying it was the hood protector. A hood protector may cause a whistle OUTSIDE the truck, but in no way can it force air INTO the truck and cause a whistle in that fashion. I can re-create this problem easily (and have it on video where you can hear it whistle), but dealer says they cant.
8 - engine idles rough when cold and idles rough after motor warm now also. Engine flat out misses bad when cold. I can re-create this problem easily (and have it on video) dealer says they cant.
9 - transmission slip at cold start-up. I have to wait 5 seconds or more after starting when cold to put it in gear, or transmission will sit there and slip. (I can re-create this problem easily and have it on video, dealer says they cant)
10 – when lowering one of the back windows, there is a terrible vibration as if something is loose behind rear seat. This is just a **** poor design and air is being trapped behind the seat. Their suggestion... I have to drop a front window or open the sliding back window... anytime I want to open a back window, or the noise will beat your ear drums to death and shake the whole truck.
11- clanking noise in rear drive train. (I can re-create this problem easily, dealer says they cant)
12 - A/C is weak and has been since I originally test drove the truck. I told them when I test drove it, and when I had it back in the shop the first 2 times. They did nothing. Sometimes it takes 30min or more to get below 60 degrees @ the vent. It could be blend door (Item #7) isnt closing properly. I was told they started it and drove it and it pulled down to 57 degrees and that is within their specs. That is BS. You cannot cool off a vehicle with 57 degree air, and had I known how cheesy their “specs” are, I would never have bought the truck.
13 - Exhaust has small leak that can be heard under truck, and leaks water from 2 or 3 spots under truck consistently on cold starts... leaving puddles in the floor. I am told the exhaust has weep holes. Ok, fine, but that does nothing for the exhaust leak that I can hear, but for some odd reason... they cant.

 

Didn't you guys read my post that's on page 3?

The reason it idles rough at start is because of the retarded timing that is supposed to decrease the time it takes for the cats to warm up.

 

Yes Jon, I saw that. Did the tune you purchased fix the issue?

 

Yes I am wondering this as well.

 

Yes it did. Hasn't done it since. I checked just to be sure and my Torque app now shows 10* at startup instead of -9*