Loss of power at 6,000 RPM 2025 GT

[Junkyard Dog]

He's referring to the power flattening out at 6,000rpm

Yes that's what I was referring to, so there may be a connection to that as to why I feel a slight stop of pulling

It appears that this is not what he was referring to. His car was actually malfunctioning. So this and all of the one throttle body closing and other theories are not what was going on.

Some sort of camshaft issue - hopefully we get some more detail about what was going wrong with the camshaft.

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[Topic]

Fixed under warranty?

Yes, it was under warranty and I found the code: p0390 and it adhered at about 12,000 miles

 

[erocker]

Ah, cam position sensor! At least the code popped up, would of been a nightmare to diagnose otherwise.

 

[24 vert]

It's easy to tell if it's wheel spinning or even clutch slipping, The rpm increases, speed doesn't in proportion.

Yep it's neither clutch slip nor wheel spin because the rate of rise of RPM slows down once you hit 6K... It could definitely be a TI-VCT issue with a failed cam phaser. I guess generally we don't spend much time on the street above 6K RPM so I don't even think the situation is lasting long enough to set of trouble code.

 

[FitmentIndustries]

Anyone else experience a slight drop in power at 6,000 RPM? I do see on dyno graphs online that torque does drop off at 6,000 RPM so maybe it's because of that? This is on a 6 speed MT trans.

You are spot on with your dyno research, that dip at 6,000 RPM is completely normal for the 2025 Mustang GT [S650]. While your horsepower is still climbing toward its 7,150 RPM peak, the Gen 4 Coyote's torque curve hits a cliff right around 5,000 RPM and drops off aggressively by 6,000 RPM. Because you are rowing your own gears with the 6-speed manual, you stay in that specific RPM window much longer than a 10-speed auto would, making you feel that sudden drop in torque as a distinct "flat spot" where the car feels like it is momentarily holding its breath.

Mechanically, this is just a quirk of how Ford tuned the S650's dual-throttle-body intake manifold and variable cam timing (TiVCT) to meet strict emissions and fuel standards. Around 6,000 RPM, the computer aggressively shifts the cams to favor top-end horsepower over mid-range grunt, while the factory software pulls back ignition timing for engine safety. It is definitely not a defect in your car, but rather the physical and electronic limits of the stock Ford calibration.

 

[Junkyard Dog]

LOL.

No.

He has a failure.

They fixed it.

Dip gone.

 

[Topic]

You are spot on with your dyno research, that dip at 6,000 RPM is completely normal for the 2025 Mustang GT [S650]. While your horsepower is still climbing toward its 7,150 RPM peak, the Gen 4 Coyote's torque curve hits a cliff right around 5,000 RPM and drops off aggressively by 6,000 RPM. Because you are rowing your own gears with the 6-speed manual, you stay in that specific RPM window much longer than a 10-speed auto would, making you feel that sudden drop in torque as a distinct "flat spot" where the car feels like it is momentarily holding its breath.

Mechanically, this is just a quirk of how Ford tuned the S650's dual-throttle-body intake manifold and variable cam timing (TiVCT) to meet strict emissions and fuel standards. Around 6,000 RPM, the computer aggressively shifts the cams to favor top-end horsepower over mid-range grunt, while the factory software pulls back ignition timing for engine safety. It is definitely not a defect in your car, but rather the physical and electronic limits of the stock Ford calibration.

Does a tune eliminate the flatness?

 

[Garcia172]

90% of this thread is completely irrelevant.

I've had the same issue. FYI... raced top levels of amateur level of racing for 18 years. This isn't some stupid "lets discuss torque/HP math thread". So stop.

The car clearly is closing down the throttle body(s) around 6k at WOT.

You can feel it. Like someone let off the gas 30%.

On this forum it's been discussed. And based on the people that delv deep into mapping the OEM ECU... the problem is a OEM programming issue and what we experience is intentional and supposed to be there.

Why? makes no sense to me....but I don't work for Ford.

So unless you remap the oem ecu or use an aftermarket ecu (we use motec), you get what Ford gives you.

 

[Topic]

90% of this thread is completely irrelevant.

I've had the same issue. FYI... raced top levels of amateur level of racing for 18 years. This isn't some stupid "lets discuss torque/HP math thread". So stop.

The car clearly is closing down the throttle body(s) around 6k at WOT.

You can feel it. Like someone let off the gas 30%.

On this forum it's been discussed. And based on the people that delv deep into mapping the OEM ECU... the problem is a OEM programming issue and what we experience is intentional and supposed to be there.

Why? makes no sense to me....but I don't work for Ford.

So unless you remap the oem ecu or use an aftermarket ecu (we use motec), you get what Ford gives you.

So this can be eliminated with any of the standard tune manufacturers?

 

[Junkyard Dog]

The car clearly is closing down the throttle body(s) around 6k at WOT.

You can feel it. Like someone let off the gas 30%.

No, it doesn't. No, I can't.

Mine pulls hard right up to the shift point. In fact, in Track Mode I never drop below 6,000 rpm.

Anyway, talk about irrelevant posts. The OP had a failure. The dealer fixed it under warranty. Now his car pulls hard up to the redline - no one of the two throttle blades slamming closed at 6000 rpm or other nonsense.

 

[Junkyard Dog]

So this can be eliminated with any of the standard tune manufacturers?

If it ever existed, then yes, it could be eliminated.

Don't you think that the tuners would be all over this making a bundle of money selling tunes to every Mustang owner in America if this was true? I would gather all of my money, hire a team of marketers and tuners and customer service folks, go into business, and make enough money to retire before the end of 2026.

Imagine learning that your acceleration drops off 30% as you go over 6,000 rpm! There is not a Mustang owner in America that would not beg me to take their money to get rid of such a curse.

 

[robvas]

If it ever existed, then yes, it could be eliminated.

Don't you think that the tuners would be all over this making a bundle of money selling tunes to every Mustang owner in America if this was true? I would gather all of my money, hire a team of marketers and tuners and customer service folks, go into business, and make enough money to retire before the end of 2026.

Imagine learning that your acceleration drops off 30% as you go over 6,000 rpm! There is not a Mustang owner in America that would not beg me to take their money to get rid of such a curse.

It wasn't 30%, but wasn't it a known fact that the DH didn't have the "feature" that the GT had where one of the TB's would slightly close at high RPM? I seem to remember it being a discovery when the cars first came out

 

[Junkyard Dog]

Actually confirmed or folks just posting about it and AI picking that up for the search engines and so folks find that result when searching in a self inflating circle of internet common knowledge that is based on nothing?

I do not know the answer, but I do not recall anybody actually being able to confirm this internet rumor.

We have tuners here. Maybe one of them could even step in and show us the line of code involved in the throttle opening.

I also recall some dyno testing where GT and Dark Horse did not show all that much difference. But it is hard to tell how well controlled the tests were. Other ones showed a significant difference, but, again, it is difficult to know how well the operators controlled all of the variables.

 

[Junkyard Dog]

There is this, from three years ago.

I am not vouching for the accuracy of it. I am just sharing the link for discussion.

https://www.mustang7g.com/forums/th...ared-dark-horse-vs-mustang-gt-vs-s550.158548/

Palm Beach Dyno went through and compared all of the differences. There are quite a few, including things most would not normally think about. For instance, the Dark Horse will allow higher oil and transmission temperatures than the GT before pulling power (about another 20 degrees F).

Maximum torque tables are higher. 59 lb ft less of torque permitted at high rpm in each gear (from 494 for the Dark Horse). The Palm Beach Dyno guy states that in good conditions and really good weather this limit may be exceeded, which may mean that the GT limits the high rpm torque, and he says it will "close the throttle a little bit" to accomplish that.

He does not show anything about the throttle closing or explain how the ECU does that or even state whether he investigated that claim before making it.

This may be where it originated.

Keep in mind that he is stating in most conditions the GT is not going to hit that torque limit, so the ECU will do nothing, meaning no difference between the GT and Dark Horse.

Also, the Dark Horse has a torque limit, too, 494, but I think what he is saying is that even on a good day, the Dark Horse is not going to exceed that limit.

 

[Junkyard Dog]

He also says that the Dark Horse has torque limits in the transmission programming, but the regular GT does not.

There are a lot of other differences in the transmission tuning.

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