2007 Mustang GT transmission limp mode?

Ktm85sx

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Bought a 2007 mustang gt 5 speed bout a month ago. Never really started ripping on it until I knew more about the car and when I do a first to second bang shift the car completely loses power, almost like it goes into a limp mode or something. It does it with traction control off, but weirdly doesn’t do it when it’s on. It’ll start bogging down if I’m spinning the tires but that’s normal. No wrench or check engine light comes on. Any thoughts? I’m WOT when I’m bang shifting. Figured if I do any racing I’ll be screwed because of this.
 

07 Boss

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First off, not sure how your bang shifting. I thought these trannies had synchros. You should use the clutch anyways if your racing, bang shifting is pretty slow especially if you don't get the rpms matched right the first try. Then you're hunting and pecking trying to get it into gear. Just use your clutch.
 

stkjock

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I'm guessing its a manual trans (keep in mind all 05-09s are 5 speeds) and a bang shift is a powershift/no-lift shift?

what's happening to the rpms when you reengage the clutch?

what bogs when you spin the tires? the motor shouldn't be, it should be spinning more freely....
 

Ktm85sx

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Thanks for the replies guys. And I should have clarified better. I’m using the clutch shifting from 1st to 2nd. It’s a manual 5 speed. It’s not like the clutch is slipping it’s literally losing power and even though I’m WOT it only revs to about 1.5k. When traction control is turned on, the engine bogs down to prevent the tires from spinning. But this problem I’m having happens with traction control off. I can still shift hard with TCS on but if I rip it too hard TCS bogs the engine down.
 

RED09GT

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Are you sure you aren't tagging the rev limiter?
The car will have a significant bog if you tag it during the shift.
 

Ktm85sx

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Are you sure you aren't tagging the rev limiter?
The car will have a significant bog if you tag it during the shift.
I don’t think I am, because I shift into second, let off the clutch, and then I floor it. It’s weird how it does it it’s not like it’s starving itself of fuel, it’ll consistently stay at 1.5k and not move up or down even though I’m floored. I’ve never seen a mustang do that because it shouldn’t matter with TCS off
 

stkjock

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Shot in the dark, did the car have mods? Some guys added a relay to trick the TCS and when it’s on it’s really off and vice versa.
 

Ktm85sx

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Shot in the dark, did the car have mods? Some guys added a relay to trick the TCS and when it’s on it’s really off and vice versa.
Well when I lose traction in the rain with TCS on it’ll kick in and not let me spin. I did some more testing and it didn’t do it but I slowed down on my shift and clutch release just a bit. Not sure why you can’t power shift in a mustang but whatever
 

Ktm85sx

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Also thanks for all the replies guys. I’m new to muscle cars as I’ve only owned trucks. Glad to know there’s people actively responding on this forum.
 

AHaze

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I noticed similar behavior with the TCS "off" in my '05 when it was stock.
When the S197 came out, I read somewhere that the stock tune wouldn't allow the throttle blades to open past a certain point while the clutch was disengaged. Not sure how true that is but it seems likely.
My car stopped falling on it's face on the 1-2 shift when I got an aftermarket tune.
 

Ktm85sx

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I noticed similar behavior with the TCS "off" in my '05 when it was stock.
When the S197 came out, I read somewhere that the stock tune wouldn't allow the throttle blades to open past a certain point while the clutch was disengaged. Not sure how true that is but it seems likely.
My car stopped falling on it's face on the 1-2 shift when I got an aftermarket tune.
Yeah I was thinking the same thing. I’m ordering the JLT and bama tuner kit next paycheck and hoping it’ll fix it. I haven’t been dogging it too hard and I’ve been making sure it’s in 2nd with my foot completely off the clutch before I floor it and it’s been acting fine now.
 

07 Boss

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Yeah I was thinking the same thing. I’m ordering the JLT and bama tuner kit next paycheck and hoping it’ll fix it. I haven’t been dogging it too hard and I’ve been making sure it’s in 2nd with my foot completely off the clutch before I floor it and it’s been acting fine now.


Stay away from Bama tuning. Far, far away.
 

mach2race

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I was thinking of adding a cold air intake and a tune, to my 05 v6. Its a stock 5speed with the only mod being a screaming demon coil, wire and NGK plugs. I was thinking Bama, but have been reading lots of negative on Bama, here of late? Is Lund, better?
 

RED09GT

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Lund is better, no debate on that. With a V6 car, you may want to talk to VMP Performance as Justin used to specialize in V6 cars quite some time ago. If I wanted a tune for a V6 car, he'd be the guy I'd talk to.
 

07 Boss

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I don't think it's a mechanical issue. I think it's a sensor or tuning issue. I'm not well versed on manual tuning but I thought you had to adjust the tune to do no-lift or power shifting. I could be completely wrong. Does the ECM control engine functions during shifting or when the clutch is in? Maybe a sticking clutch sensor?
 

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