What did you do to your S550 Mustang today?!

Cobra Jet

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It drives fine and pulls hard. It's only at stop lights at idle. Doesn't matter what mode I'm in (normal, track, sport, etc.). It also doesn't do it when I first fire up the car it's after driving it. I got half a km down the road yesterday from the dealership and it stalled at the lights.

Here is an example of what it does except without the actual stall part but if I had kept recording it may have.



Also, if I give it a little gas when it starts doing this it doesn't stall. It's like I have to feather the accelerator.
@MCS

2 checks:
- Has anyone pulled plugs to read and see condition of each?
- Has anyone done a wiggle test to make sure there aren't any loose connectors, loose grounds or even checked harnesses to make sure there isn't any chafing or damages?

Aside from the obvious above. . .

- Did the shop bother to check the CHT or MAF values to make absolutely sure they are within spec? The problem with some sensors is that even if they are sporadically faulty, they do not always throw a code and sure they "look good" but doesn't always mean they are "good".

- Also have them check the crank position sensor. There's been many threads on here where folks are having drivability issues and it's been found that the crank position sensor is faulty. Either the body is found to be cracked, the plug/connector pins found to be loose or debris is stuck to the magnetic end that reads the tone ring.

2 other things to check:
- O2 sensors. Again even if they are sporadically faulty, they don't always throw a code. There's been plenty of threads on here with M6Gers finding faulty O2's and once replaced, the issues clear up.

- Coil packs. A general misfire code is a P0300, which is sometimes "normal" according to Ford's misfire strategy or it could relate to other sensors if having to do a pin out trace. A misfire code of a P0301-P0308 is a specific cylinder misfire. Now I'm just throwing that out there in the event you do a scan yourself and see any such codes. But what I want you to check is the physical condition of each coil pack. There were threads on here where M6Gers had found melted coil packs. Once pulled from the head check them thoroughly, not only check for a visible and obvious "melt" of the exterior casing - BUT use a high powered LED light and go over the entire casing to make sure there aren't any fine hairline cracks. Any breach of the coil pack will cause drivability issues. If a coil pack has a crack, once it gets hot the crack is going to expand allowing an arcing condition.

Ok, yea the above is a lot to absorb, BUT those are going to be the most common Coyote issues.

Since your only experiencing the problem AFTER the car is getting to optimum operating temps, the issue could be sensor related.

 

MCS

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@MCS

2 checks:
- Has anyone pulled plugs to read and see condition of each?
- Has anyone done a wiggle test to make sure there aren't any loose connectors, loose grounds or even checked harnesses to make sure there isn't any chafing or damages?

Aside from the obvious above. . .

- Did the shop bother to check the CHT or MAF values to make absolutely sure they are within spec? The problem with some sensors is that even if they are sporadically faulty, they do not always throw a code and sure they "look good" but doesn't always mean they are "good".

- Also have them check the crank position sensor. There's been many threads on here where folks are having drivability issues and it's been found that the crank position sensor is faulty. Either the body is found to be cracked, the plug/connector pins found to be loose or debris is stuck to the magnetic end that reads the tone ring.

2 other things to check:
- O2 sensors. Again even if they are sporadically faulty, they don't always throw a code. There's been plenty of threads on here with M6Gers finding faulty O2's and once replaced, the issues clear up.

- Coil packs. A general misfire code is a P0300, which is sometimes "normal" according to Ford's misfire strategy or it could relate to other sensors if having to do a pin out trace. A misfire code of a P0301-P0308 is a specific cylinder misfire. Now I'm just throwing that out there in the event you do a scan yourself and see any such codes. But what I want you to check is the physical condition of each coil pack. There were threads on here where M6Gers had found melted coil packs. Once pulled from the head check them thoroughly, not only check for a visible and obvious "melt" of the exterior casing - BUT use a high powered LED light and go over the entire casing to make sure there aren't any fine hairline cracks. Any breach of the coil pack will cause drivability issues. If a coil pack has a crack, once it gets hot the crack is going to expand allowing an arcing condition.

Ok, yea the above is a lot to absorb, BUT those are going to be the most common Coyote issues.

Since your only experiencing the problem AFTER the car is getting to optimum operating temps, the issue could be sensor related.
Thanks, @Cobra Jet I'll pass this info along. I did write them on the weekend to point them in the direction of the cam phasers however I'll summarize your info here and pass that along to them as well!
 

MCS

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2 checks:
- Has anyone pulled plugs to read and see condition of each?
- Has anyone done a wiggle test to make sure there aren't any loose connectors, loose grounds
Spoke with Ford today. Today's update; the dealership is having Roush send them some new plugs. They are going to swap that and see if that resolves the issue. If it doesn't then they are going to have a meeting with the higher-ups at the dealership to find out what is going to happen next as they have had my car since Sept 18th (except the 3 days I had it over a weekend when it was first installed).

So far no word on the Cam Phasers or all the other recommendations you guys have put forth but we'll see. I think they are looking to eliminate the easy stuff first (like swapping plugs) before it comes down to ripping the engine apart to replace those phasers; makes sense from a cost perspective. The dealership has probably blown its profits on the labour so now it's a matter of customer satisfaction and also figuring this out for future installs.
 
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MD18EcoStang

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You are correct....Like lots of members on here I have two sets of tires and run 285/35/19 square during the summer because I want a wider more aggressive look. And if it snows out I'll drive my 4x4 truck.
Did the same - PS AS4s for winter (in 275/35-19) and Nitto summer tires in 285. Very happy. Got the same questions, too, about why not buy actual winter/snow tires... Because my need is just for tires that are reliable in colder weather. No need to ever drive it in snow!
 


rxryanm

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Because my need is just for tires that are reliable in colder weather. No need to ever drive it in snow!
That's still winter tires lol. You don't have to drive in the snow to get the benefits of the tire that uses a compound that stays flexible in temps < 45*F.

If you only had 1 set of tires, sure. But I'll always advocate for winters for winter and summers for summers if you're going to have two sets. I did bought winters when I bought my Mustang and am now definitely a believer in them lol.
 

Ret_Sgt

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Looks good. Maybe change the "5.0" side badge to black.
I actually like the splash of chrome that matches the pony and the GT.
 
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MD18EcoStang

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That's still winter tires lol. You don't have to drive in the snow to get the benefits of the tire that uses a compound that stays flexible in temps < 45*F.

If you only had 1 set of tires, sure. But I'll always advocate for winters for winter and summers for summers if you're going to have two sets. I did bought winters when I bought my Mustang and am now definitely a believer in them lol.
I hear ya! But, I'm good! Felt very safe and reliable with the A/S tires last year. Excellent grip. Maybe if it was my DD, but it's mostly a "when I feel like it" car.
 

Stage_3

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Had the day off today. (Scheduled vacation day. I needed it.)
Couldn't have picked a better day as it is 74 degrees out here IN OCTOBER, with full sunshine,.......so I took the beast out for a quick little rip after lunch.
 

16Fastback

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20221012_125505.jpg

Car shows came to a end
So I took her to the winter home.
 

ice445

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Had the day off today. (Scheduled vacation day. I needed it.)
Couldn't have picked a better day as it is 74 degrees out here IN OCTOBER, with full sunshine,.......so I took the beast out for a quick little rip after lunch.
Yeah the weather here has been literally perfect. 70s during the day and 45-50 at night. I'm taking the long way home every night lol
 

 
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