Engine stutter when aggressively accelerating.

[Shecallzmipapi]

Hey gues not very good with cars but I need help please. I have a 2014 fiesta st that just started stuttering when I aggressively accelerate. I took it to a shop and they told me it's due to not having enough back pressure.(I know it's stupid to not have one) I don't have an exhaust on it currently because I just sold mine.i don't drive it very often but I've driven it maybe 8 times without the exhast and it worked great still a bit load but great then all of a sudden shuddering unless I drive like an old man. Any thoughts or ideas and I would love to hear them I don't want to have to buy another exhaust just to sell the car soon if someone has any other ideas what could be wrong I'd live to hear it.

 

[TyphoonFiST]

Hey gues not very good with cars but I need help please. I have a 2014 fiesta st that just started stuttering when I aggressively accelerate. I took it to a shop and they told me it's due to not having enough back pressure.(I know it's stupid to not have one) I don't have an exhaust on it currently because I just sold mine.i don't drive it very often but I've driven it maybe 8 times without the exhast and it worked great still a bit load but great then all of a sudden shuddering unless I drive like an old man. Any thoughts or ideas and I would love to hear them I don't want to have to buy another exhaust just to sell the car soon if someone has any other ideas what could be wrong I'd live to hear it.

Does it still have a catalytic converter? That's what really causes most of the back pressure*

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[Shecallzmipapi]

Does it still have a catalytic converter? That's what really causes most of the back pressure*

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Yeah I still have it installed

 

[TyphoonFiST]

Yeah I still have it installed

Is there any codes?

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[TyphoonFiST]

I could also see this as an issue for the rear o2 sensor seeing way to much Air that it thinks there may be a leak in the exhaust system. If it were me...I go on fleabay and buy a $200-300 cat back and install that. Then just past the cost on to the Buyer. But hey...Thats just what I'd do...You do you!

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[Shecallzmipapi]

N

Is there any codes?

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No codes at all that's the hard part.ithink it might be the manifold

 

[TyphoonFiST]

N

No codes at all that's the hard part.ithink it might be the manifold

Manifold?

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[Shecallzmipapi]

Manifold?

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Exhaust manifold.if that has a leak I could be loosing pressure but idk .I just know if it was a sensor it would be throwing a code so I don't think it's that

 

[TyphoonFiST]

Exhaust manifold.if that has a leak I could be loosing pressure but idk .I just know if it was a sensor it would be throwing a code so I don't think it's that

Not necessarily *

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[FJ16]

Surprised it's not throwing any codes, but I would imagine it's directly related to running no exhaust - I'd make sure no O2 sensors were damaged/removed. Does it always happen at a certain RPM or speed? If you give it light throttle does it ever appear, or only under significant load?

 

[Shecallzmipapi]

Surprised it's not throwing any codes, but I would imagine it's directly related to running no exhaust - I'd make sure no O2 sensors were damaged/removed. Does it always happen at a certain RPM or speed? If you give it light throttle does it ever appear, or only under significant load?

It only happens with decent load. Rpms don't really matter just when I floor it.light throttle it works like a charm still no problems

 

[Shecallzmipapi]

Not necessarily *

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U mean it wouldn't throw a code or loose pressure?

 

[TyphoonFiST]

U mean it wouldn't throw a code or loose pressure?

That it wouldn't throw a code* depends on manufacturer threshold for codes to be set and we are talking about fomoco here too*

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[Shecallzmipapi]

That it wouldn't throw a code* depends on manufacturer threshold for codes to be set and we are talking about fomoco here too*

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Ok I'll check maf in a sec thank you guys I appreciate all the help

 

[the duke]

It’s not showing codes because there isn’t a visible check engine light or you literally plugged in a scan tool and there are zero error codes on the ECU?

 

[Shecallzmipapi]

It’s not showing codes because there isn’t a visible check engine light or you literally plugged in a scan tool and there are zero error codes on the ECU?

I have used a scanner and there are no codes the check engine light is working as well it just isn't pulling any code.

 

[TyphoonFiST]

The check engine light is on?

 

[Shecallzmipapi]

I have used a scanner and there are no codes the check engine light is working as well it just isn't pulling any code.

I've checked the maf sensor and spark plugs redone all my fluids looked for leaks from my air filter.ive begun to start worrying it's the o2 fuel ratio sensor as I hear that's dangerous to leave like that

 

[Shecallzmipapi]

The check engine light is on?

No it just works but it is not on and I pull 0 codes .like when u first start the car all the lights come on I mean

 

[TyphoonFiST]

The ST's are MAP based systems NOT MAF* The Part that looks like a MAF is a Intake temp sensor pretty much...FYI.