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Discussion Starter #1
Hey members.
first I would apologize for my English. I live in Denmark and english is my third language. So I would like to apologize in advance.

I bought my second Mustang a couple of months ago, and it has been acting a little weird lately.
it's a 2014 3.7V6 Mustang

First thing is, and maybe it got something to do with the second thing.
When I press down my speeder, when I release my foot, it downshifts in 3 steps, ........ ...... ... like I tried to "draw" with the spots...

The second thing is that after I installed a Magnaflow axle back exhaust, and only that.
my idle is ticking a little bit higher, and my car went from a normal miles per gallon. To something that a humvee edition 1 uses .. Dont know what it is in miles since we use kilometers. But the normal is 8-9km per liter, and have been doing this for the 2 months I have owned the car up till the day I changed the axle back and it's down to 1-4 km per liter.
When I check the avg miles per gallon in the display in the car, its worst when I'm holding at a red light, the avg drops a 0.1liter every second.
no engine light has come up, or anything .

So do maybe one of you have an idea ?
the thing is, in Denmark we have so little mechanics that know anything about American cars, so the ones we have charge 120$ an hour just to find the problem.
 

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Hey members.
first I would apologize for my English. I live in Denmark and english is my third language. So I would like to apologize in advance.

I bought my second Mustang a couple of months ago, and it has been acting a little weird lately.
it's a 2014 3.7V6 Mustang

First thing is, and maybe it got something to do with the second thing.
When I press down my speeder, when I release my foot, it downshifts in 3 steps, ........ ...... ... like I tried to "draw" with the spots...

The second thing is that after I installed a Magnaflow axle back exhaust, and only that.
my idle is ticking a little bit higher, and my car went from a normal miles per gallon. To something that a humvee edition 1 uses .. Dont know what it is in miles since we use kilometers. But the normal is 8-9km per liter, and have been doing this for the 2 months I have owned the car up till the day I changed the axle back and it's down to 1-4 km per liter.
When I check the avg miles per gallon in the display in the car, its worst when I'm holding at a red light, the avg drops a 0.1liter every second.
no engine light has come up, or anything .

So do maybe one of you have an idea ?
the thing is, in Denmark we have so little mechanics that know anything about American cars, so the ones we have charge 120$ an hour just to find the problem.
First of all when you are stopped at idle you are getting zero kilometers per liter so dropping KPL is normal when stopped. An axle back should not change much but the sound but you should not trust the computer readout so check how many kilometers you get from a tankful. I have no idea what you mean about your transmission. They normally downshift when you press the accelerator pedal to increase engine RPM's and acceleration. If it is downshifting too much that would decrease fuel efficiency though. The cars computer controls the shifting of the automatic, do you have a tune ?
 

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Discussion Starter #3
First of all when you are stopped at idle you are getting zero kilometers per liter so dropping KPL is normal when stopped. An axle back should not change much but the sound but you should not trust the computer readout so check how many kilometers you get from a tankful. I have no idea what you mean about your transmission. They normally downshift when you press the accelerator pedal to increase engine RPM's and acceleration. If it is downshifting too much that would decrease fuel efficiency though. The cars computer controls the shifting of the automatic, do you have a tune ?
Thanks for the reply.
I dont know how to explain it in english very well.
But when it downshifts it does it in 3 hard stops. Before it smooths down the gear and speed I'm at.
My mustang from 07 didn't do that.
I have a transmission company look at the transmission and they couldn't find anything wrong with the transmission.

From a full tank of gas I get about 180km, that's about 111 miles.
When I bought it(have tanked it about 6 full tanks in 2 months) I got 400-500km in a full tank. That's 240-300 miles
If the converter I Used was correct.

No tune that I know of, it was imported in 2018 from the states and have been standing still since april this year, where I bought it. But it looks completely stock.
It has 45k miles.
When I got it, the brakes where changed, every liquid changed, brake/engine/AC/transmission.
 

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Thanks for the reply.
I dont know how to explain it in english very well.
But when it downshifts it does it in 3 hard stops. Before it smooths down the gear and speed I'm at.
My mustang from 07 didn't do that.
I have a transmission company look at the transmission and they couldn't find anything wrong with the transmission.

From a full tank of gas I get about 180km, that's about 111 miles.
When I bought it(have tanked it about 6 full tanks in 2 months) I got 400-500km in a full tank. That's 240-300 miles
If the converter I Used was correct.

No tune that I know of, it was imported in 2018 from the states and have been standing still since april this year, where I bought it. But it looks completely stock.
It has 45k miles.
When I got it, the brakes where changed, every liquid changed, brake/engine/AC/transmission.
Your english is fine it is the problem that is weird. It sounds like you are in "hill descent" mode. In that mode the transmission downshifts to allow engine braking going down hills and it also disables 6th gear. On my 2012 there is a button on the side of the shifter that engages it. Your gas mileage is best when the engine is turning as slowly as possible for the speed. Does your car shift into 6th gear when you reach you cruising speed? My car is below 2000 RPM at 60 MPH in top gear and I have a 3.36 rear axle gear. A stock gear would be even lower RPM
 

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Discussion Starter #5
Your english is fine it is the problem that is weird. It sounds like you are in "hill descent" mode. In that mode the transmission downshifts to allow engine braking going down hills and it also disables 6th gear. On my 2012 there is a button on the side of the shifter that engages it. Your gas mileage is best when the engine is turning as slowly as possible for the speed. Does your car shift into 6th gear when you reach you cruising speed? My car is below 2000 RPM at 60 MPH in top gear and I have a 3.36 rear axle gear. A stock gear would be even lower RPM
What button is that ? Can you show me a picture ? The only buttons I have is the plus and negative to change the gears manually.

I'm.going tomorrow on the highway, so I will check if its changing to sixth gear.. its almost midnight here in Denmark, and I'm going to work at 7..
Maybe I found a guy who would put a tester on it to see if something is wrong.

Just a little off topic question.
The previous car I owned was a Golf GTi, but when I put the the key in, every light would turn on (airbag/engine etc). And then turn off, and then I would turn the motor on .
Dont know if its normal in a stang or american cars in general, but I do the same, put the key in, wait for the lights to turn off before I start the motor but the only thing that dont turns off is the engine light.
Is that normal ?
 

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The thing that you have the engine light to fix is normal,

the button that says iguanaman3 is the one that you say to increase and decrease speed manually

your gears are 2.7 so your consumption should be around 400 km (240 miles)

What makes you change ,,,, what I have done is change the ATF of it, (use mercon LV) empty it and fill the oil pan several times, it is easy, with a small electric pump, take out where it is the small level bar (passenger side) the atf and put exactly the same that has taken out more about 100ml more (3 ounces) in the same way. If you want to change the filter, you do the same, when it is empty, remove the crankcase and see the filter and change it, the gasket is reusable, check it well



luck
 

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Discussion Starter #7
The thing that you have the engine light to fix is normal,

the button that says iguanaman3 is the one that you say to increase and decrease speed manually

your gears are 2.7 so your consumption should be around 400 km (240 miles)

What makes you change ,,,, what I have done is change the ATF of it, (use mercon LV) empty it and fill the oil pan several times, it is easy, with a small electric pump, take out where it is the small level bar (passenger side) the atf and put exactly the same that has taken out more about 100ml more (3 ounces) in the same way. If you want to change the filter, you do the same, when it is empty, remove the crankcase and see the filter and change it, the gasket is reusable, check it well



luck
I will try doing the ATF oil change, because I think they didn't change it, even when they say they did.
Should the spark plugs maybe have been changed, after 2 years of not even starting the car..

But are those buttons not just for decrease and increase the shifting manually ?
Because I have been using it sometimes..
 

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I am European too (Spain). Change the atf, change the rear differential fluid and add an antifriction additive, change the spark plugs (ngk iridium) if it has been stopped for two years, you will have the injectors and fuel lines with residues, buy a good injector cleaner (I use the bard or liquimoly, you put the first bottle with about 15 liters of gasoline in the tank and the second bottle with half a tank, repeat the operation at 2000km. I also recommend cleaning the engine by dento when changing the oil (an additive to remove sludge and ash) and change the oil at a maximum of 10,000 km or when the oil gauge tells you what is between 20 and 10% ub, Use the 5w20 (I used castrol but now I use mannol) obviously change the oil and air filters, and clean the throttle body, You should watch the AFR that the car shows you when you are driving it can tell you if you are rich or poor
 

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Discussion Starter #9
Update:
Found one with a universal obd tester. As thought, no codes. Since the engine light never had shown.
But both of the 02 sensors in front was static. They only went from 0.9 down to 0.78. In idle and pressing the speeder down. They didn't move numbers. So I'm going to change those and see if that helps ..
 

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You should have the up and down button for the gears to shift manually and the one that puts on the hill decent. On my truck that is a Select Sift it will bang the gears pretty good when you slow down and it seems to drop one gear at least every time you hit the brakes.
 

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Discussion Starter #11
You should have the up and down button for the gears to shift manually and the one that puts on the hill decent. On my truck that is a Select Sift it will bang the gears pretty good when you slow down and it seems to drop one gear at least every time you hit the brakes.
s-l960_(4)1.jpg

My shifter looks like that, and there's no other button on the other side

Not sure what you guys mean ?
 

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Discussion Starter #12
I am European too (Spain). Change the atf, change the rear differential fluid and add an antifriction additive, change the spark plugs (ngk iridium) if it has been stopped for two years, you will have the injectors and fuel lines with residues, buy a good injector cleaner (I use the bard or liquimoly, you put the first bottle with about 15 liters of gasoline in the tank and the second bottle with half a tank, repeat the operation at 2000km. I also recommend cleaning the engine by dento when changing the oil (an additive to remove sludge and ash) and change the oil at a maximum of 10,000 km or when the oil gauge tells you what is between 20 and 10% ub, Use the 5w20 (I used castrol but now I use mannol) obviously change the oil and air filters, and clean the throttle body, You should watch the AFR that the car shows you when you are driving it can tell you if you are rich or poor
I have now bought 2 of the liqui Moly and would do the operations after changing the o2 sensors.

I quite dont understand the last bit you wrote, "You should watch the AFR that the car shows you when you are driving it can tell you if you are rich or poor"
Not entirely understanding..
 

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I have now bought 2 of the liqui Moly and would do the operations after changing the o2 sensors.

I quite dont understand the last bit you wrote, "You should watch the AFR that the car shows you when you are driving it can tell you if you are rich or poor"
Not entirely understanding..
[/CITAR]

It depends on which package is yours, if it is the "premium" in the center it show you a menu with many options, in one of them you can monitor the air fuel ratio (AFR) which must be over 14.1, below you go rich, above you go poor. If you are accelerating and you see that it falls off large, or vice versa, then you should check the O2 sensors (an error in the frame would occur), a vacuum leak (an error in the frame would result) or a dirty injector or defective
 

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Discussion Starter #16
I just found out that my motor oil smells badly of benzin. So maybe that's the problem with the car
 

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My internet 'guess' are 2 things. First 'guess' is a stuck fuel injector and my second 'guess' is your PCM is going bad, making your timing off and could be your transmission problem also :(. These are just my 'guess' on things I would be checking out first ……...Good luck and let us know what you find out......
 

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Discussion Starter #18
I got the premium model. So I would take a look at it when I go home..
But no errors have occurred, meaning that I haven't got any errorcodes on a tester.
 

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My internet 'guess' are 2 things. First 'guess' is a stuck fuel injector and my second 'guess' is your PCM is going bad, making your timing off and could be your transmission problem also :(. These are just my 'guess' on things I would be checking out first ……...Good luck and let us know what you find out......
I will definitely inform, that the problem are, when I find out ..
I have 2 questions..
PCM ? That's the computer right ?
And how can the transmission affect the fuel ?
 

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I will definitely inform, that the problem are, when I find out ..
I have 2 questions..
PCM ? That's the computer right ?
And how can the transmission affect the fuel ?
Yes, the computer. Ford calls it a Eec Module on their web site, almost $800 :(. I 'think' it controls the Transmission and the Engine, I could be wrong :). My Tunes changes the way the transmission shift through the PCM (Eec), so I figure it must control the Motor and Transmission. Could be why your transmission is shifting strange. I'm just guessing...…….
 
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