Cold start ?issue?

[GT2022]

Wellllll I let the car sit for another day and a half, this time with no car wash and the problem still happened, so I’m ruling out the car wash/cold weather possibly freezing something open/closed. I managed to get a few more videos, not only did it do the weird bouncing rpm thing when it was initially started, I figured I’d try hitting the gas while it was bouncing and it did nothing. Literally nothing, had the pedal to the floor and it didn’t even flinch, just kept bouncing away, I restarted it and still was bouncing, so I threw it in drive and crawled around the block, the rpm’s settled somewhat BUT once it settled down it sat around 500-600rpm idle and if I gave it gas, like foot to the floor, it would only rev up to 1k and start doing it’s bounce… just curious if anyone’s experienced/seen this before, setting an appointment with ford but I’d like some opinions so I know what I can expect from the dealer. Videos below

Original video I posted the other day/outside audio:

video from todays initial start up/restart/inside dash view:


Flooring it after initial start with no response whatsoever:


After rpm’s have settled, flooring it and only going up to 1k rpm and bouncing:

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[Mike Pfeifer]

Vacuum leak?

Edit:

I guess I should clarify - airmass reading vs. actual airmass discrepancy?

 

[GT2022]

Vacuum leak?

Edit:

I guess I should clarify - airmass reading vs. actual airmass discrepancy?

Seems to only happen when the car sits for more than a day though? if I start it every morning for work there’s no issue, over the weekend if I don’t go out Sunday or like this week I got a ride with a buddy to work so the car sat for a day and a half/2 days basically and that’s when it happens

 

[KingKona]

Take. It. To. The. Dealership.

It's under warranty, let them fix it.

 

[GT2022]

Take. It. To. The. Dealership.

It's under warranty, let them fix it.

Yea I’m gonna have to try a different dealer and I should of linked my previous thread, I had it to the dealer already for this issue (but with no video) and they said they couldn’t replicate the issue and told me “it’s probably normal, it was probably colder that day” and sent me on my way :/

 

[Dfeeds]

That's definitely not normal. Does it do this even if you're in neutral?

Mine could sit in legitimate -15 F (-30 with wind chill) temps for over 12 hours and would fire right up without even a stumble. Unless you're using old summer blend gas, it shouldn't struggle to start in the cold. Assuming stock configuration, that is.

Regardless, I second finding an alternative dealership and saving yourself the headache.

 

[KingKona]

Yea I’m gonna have to try a different dealer and I should of linked my previous thread, I had it to the dealer already for this issue (but with no video) and they said they couldn’t replicate the issue and told me “it’s probably normal, it was probably colder that day” and sent me on my way :/

Show them those videos. Let them scan the car for codes.

 

[GT2022]

That's definitely not normal. Does it do this even if you're in neutral?

Mine could sit in legitimate -15 F (-30 with wind chill) temps for over 12 hours and would fire right up without even a stumble. Unless you're using old summer blend gas, it shouldn't struggle to start in the cold. Assuming stock configuration, that is.

Regardless, I second finding an alternative dealership and saving yourself the headache.

seems to be only when the car sits for an extended period of time rather than the cold. If i start it day by day for work it doesn't skip a beat in any weather, it was only recently i started parking it on sundays so it sits for a solid 24h+ until i leave for work monday morning and that's when it happens so i dunno tbh. And yea i can get in sometime within the next week or two so we'll see, was just fishing around to see if maybe someone's experienced something similar. Appreciate it!

 

[ORRadtech]

So, in your first thread you said it had only done it o ce or twice. Has it now become reliably repeatable?
If so and you can define what needs to happen a dealer should be able to experience the problem. Perhaps arrange to drop the car off on a Friday or Saturday evening so it has a chance to sit for a day or more before it's started.

 

[AZlb5.0]

I didn’t know Mustangs could lope with out a tune jk

but all joking aside, that’s crazy that it seems that your throttle is completely deactivated when it’s doing this. There’s definitely an issue somewhere in the computer. With that amount of startup disruption and no ability for the throttle to engage it has to be more then just a relay.

 

[GT2022]

So, in your first thread you said it had only done it o ce or twice. Has it now become reliably repeatable?
If so and you can define what needs to happen a dealer should be able to experience the problem. Perhaps arrange to drop the car off on a Friday or Saturday evening so it has a chance to sit for a day or more before it's started.

yea it would seem so, I think it's when the car sits for more than a day or so (I have no idea why that would matter but i also have no idea what I'm talking about lol.) every time it's happened now has been when the car was last driven saturday night and not started until monday morning, if i start it day by day with only like a 12-14 hour space between starts it starts no problem, and yea that's the plan hopefully they can replicate it now that i've narrowed it down a little + i have videos of it now

 

[GT2022]

I didn’t know Mustangs could lope with out a tune jk

but all joking aside, that’s crazy that it seems that your throttle is completely deactivated when it’s doing this. There’s definitely an issue somewhere in the computer. With that amount of startup disruption and no ability for the throttle to engage it has to be more then just a relay.

I have honestly wondered if a simple stock tune might actually fix a bunch of the little gremlins i seem to have lol, and yea the no throttle response made it so much more confusing for me lol, 0 response while it was bouncing.. but then after i drove it around the block and parked it, it would only let me rev up to 1k and then bounce??? that was just as strange as the no response

 

[Mike Pfeifer]

So your car is not stock?

 

[GT2022]

So your car is not stock?

100% stock

 

[Cobra Jet]

Tell the Dealership they need to do a PCM reset. Sounds like something with the Torque Table is corrupted, which is part of the cold start PCM process.

Is the car throwing any codes at all?

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