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My car surges/bucks/accelerates on its own pretty badly when the engine is cold and I'm trying to drive slowly. It mostly happens in parking garages and parking lots. Has anyone else experienced this with their SFE? Build date of 3/15.
 

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I've noticed this a bit, only when it's totally cold (as you suggest) and only at very low speeds. I just basically ignore it, but if there's a solution, I'd like to hear too.
 

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Mines done this for along time. Only does it a few seconds. Oct 2013 build date.
 

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Same here. It's more pronounced before closed loop operation. It hasn't bothered me. It acts similar as my other cars with larger map sensors and re-scaled ECU's, but only for the first couple minutes of cold operation.
 

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Mine has never done this. I have a February 2014 build.


Sent from my iPhone using Tapatalk
 

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lol how is it user error just because your foot is on the throttle?

brand new 2016, mine does it. but i found it's only after the vehicle has been started for the day, and allowed to cool down.
 

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So far *knock on wood* it hasnt done it to me yet, or if it did thanks to the looooovely /s roads here in california i cant sense it. In no matter what car on some of these roads it feels like its bucking or surging.
 

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lol how is it user error just because your foot is on the throttle?

brand new 2016, mine does it. but i found it's only after the vehicle has been started for the day, and allowed to cool down.
because your foot is moving the throttle from the motion of the car even if you think its not. next time it happens take your foot right off the tthrottle and see if it stops.

if its a manual transmission the car will not stall out. Car has anti stall feature.
 

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because your foot is moving the throttle from the motion of the car even if you think its not. next time it happens take your foot right off the tthrottle and see if it stops.
Now I understand what you are saying here, about the bucking causing your foot to exacerbate the problem, but it's not a buck it's a surge, and it's so slight it would be imperceptible to a passenger.
 

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Now I understand what you are saying here, about the bucking causing your foot to exacerbate the problem, but it's not a buck it's a surge, and it's so slight it would be imperceptible to a passenger.
I personally think the surge happens because of the anti stall feature. there are times I find my car will just take off faster then I would be expecting. but only when cold.
 

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Mine does it. Only when I very first start it up and immediately drive away and when it's cold. I believe it's the fast idle trying to keep the revs up when your lugging it in 1st, something to do with the pathetic electronic throttle body most likely.
 

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I can feel it as well when just started the car and giving very slighty throttle.

Speaking of cold starts, can anybody else hear a diferent ugly noise when starting the engine on cold mornings? In mine, I can hear a disturbing knocking that dissapear when the engine is at service temperature. Should I worry?
 

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Not sure if anyone is still looking at this, but I'm getting some bucking/surging when I first start the car and drive away. The car always starts without a problem and idles fine, the only issue is when it's in gear.
2014 SFE, 5 speed manual.
Once one bar comes up on the temperature gauge it seems to even out. It almost feels like the gas pedal is incredibly sensitive when the car is trying to warm up, and even with constant pedal pressure in first gear it will start to surge at some point over 2000rpm. I usually end up clutching in and coasting to avoid the bucking until the car warms up, but it's still not something that should be happening in the first place.
 

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Discussion Starter #15
Mine still does it to this day. Sometimes it takes off on its own so quickly it can be dangerous. It's something that should not happen on a stock car with a stock computer tune. It's very annoying. The tune I built for my h/c/i supercharged Mustang works better than my stock SFE's.

The best thing I've found to help with the problem is to be ready to disengage the clutch.
 
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