Car kicks/jerks arounf 30 mph

So it's been happening more and more frequently. When I'm driving around 30 mph or decelerate from around that speed the car would jerk forward a bit. Like if I need to slow down or if I'm at a stop and go to about 30 mph I'll feel it kick forward and back.

Does anybody know why it does that and does anybody have any advice.

Its a V6, auto and I have MPT tune on that's it.

Mine has done that since I have gotten the car, and was worse when I put a tune on it the tunes for these cars make the cars throttle response very touchy you can email your tuner to have it adjusted to have less throttle response and it will fix most of it, I have just learned how to control it for the most part but never any issues with the car.

JohnnyBoy said:

So it's been happening more and more frequently. When I'm driving around 30 mph or decelerate from around that speed the car would jerk forward a bit. Like if I need to slow down or if I'm at a stop and go to about 30 mph I'll feel it kick forward and back.

Does anybody know why it does that and does anybody have any advice.

Its a V6, auto and I have MPT tune on that's it.

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Oh hey I thought it was just me. I have auto with mpt. Now mine is a bit different. If i accelerate to 20-25mph but let off and then throttle up to 30mph, it feels like the trans doesn't know what to do for a bit. It feels like it is just spinning then suddenly it shifts and the car just jerks into a hard shift just like how you describe it. This only happens in D with the mpt tune which I can easily replicate every time. It doesn't happen with stock tune. It also doesn't happen if I just accelerate to 30mph with mpt tune. Not sure if it happens in S because I have never felt it.

Fuse said:

Oh hey I thought it was just me. I have auto with mpt. Now mine is a bit different. If i accelerate to 20-25mph but let off and then throttle up to 30mph, it feels like the trans doesn't know what to do for a bit. It feels like it is just spinning then suddenly it shifts and the car just jerks into a hard shift just like how you describe it. This only happens in D with the mpt tune which I can easily replicate every time. It doesn't happen with stock tune. It also doesn't happen if I just accelerate to 30mph with mpt tune. Not sure if it happens in S because I have never felt it.

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In your case with auto trans I would assume its your electro overdrive being confused on if it should go or not go. I put a Boomba 70 duro tranny mount on this weekend and it seemed to have helped alot but if you go that route beware if you dont like sound because you can hear everything the tranny does which I like it but you may not.

I thought it was just engine braking? My manual GTI would do the same thing when I let off the throttle. The throttle response on the MPT isn't "touchy" to me. Maybe if you have shorter gears, but on the 3.15s there's plenty of pedal travel and it isn't touchy.

I think what you're feeling is normal.

TURTL3 said:

I thought it was just engine braking? My manual GTI would do the same thing when I let off the throttle. The throttle response on the MPT isn't "touchy" to me. Maybe if you have shorter gears, but on the 3.15s there's plenty of pedal travel and it isn't touchy.

I think what you're feeling is normal.

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I am running 3.55 gears. However there are so many threads reporting the same issue from 2011 3.7 all the way to 2017 models. Which obviously came out to the conclusion it is normal and when asking MPT they have said they set it up that way.

BE6Pony said:

I am running 3.55 gears. However there are so many threads reporting the same issue from 2011 3.7 all the way to 2017 models. Which obviously came out to the conclusion it is normal and when asking MPT they have said they set it up that way.

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I see. FWIW it does the same thing to me stock as well. I think it's just the engine braking kicking in but idk for sure of course.

TURTL3 said:

I see. FWIW it does the same thing to me stock as well. I think it's just the engine braking kicking in but idk for sure of course.

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When mine does it its jerky when I try to ease on or off the pedal and sounds like the clutch and gears all thrown all over the place but again no issues and its been like that forever.

Mine does the same. Only does it in the lower rpms, usually like when I’m in a neighborhood. I just figured the loss of low end power from my LTs was causing it

Mine did the same, for manual, it kicks in when the RPM drops to around 1200rpm to help the car not to stall. This is common for a manual car. And the kicks and jerks happen when I released the throttle in first gear, it is also normal for a manual car.

Pertaining to manuals, when you get off the gas while in gear the fuel gets shut off and your momentum keeps the engine going. When that happens I get a strong jerk and then another when I get back on the gas. The rare occasion the ecu has a brain fart and doesn't cut the fuel when engine braking it's smooth as butter. Watching the A/F can tell you when the fuel has been cut off. I'm not sure if the autos have this "feature* too but I don't think so

ChiTownStang26 said:

Pertaining to manuals, when you get off the gas while in gear the fuel gets shut off and your momentum keeps the engine going. When that happens I get a strong jerk and then another when I get back on the gas. The rare occasion the ecu has a brain fart and doesn't cut the fuel when engine braking it's smooth as butter. Watching the A/F can tell you when the fuel has been cut off. I'm not sure if the autos have this "feature* too but I don't think so

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How did you figure that out? I have been wondering why my car does this ever since I got the thing, out of everything with the car I feel like the jerky on and off the gas/clutch is the most annoying thing in the world makes you look like you don't know how to drive stick.

[MENTION=21090]BE6Pony[/MENTION]

I believe most manuals in the past couple years do that to improve gas mileage. If you watch the A/F ratio when you let off the gas in gear you'll see it go to 20.0 which is as high as it goes meaning all air and no fuel. Maybe 1 out 100 times the fuel wouldn't cut off, no jerk would happen, and the A/F would be normal (14.0) for me. So I figured out that jerk was from the fuel cut off and I'm guessing the driveline tenses up or something because it's being forced to turn your crank. The jerk is from fuel being shut on and off, why it's jerking cause off that is me guessing.

ChiTownStang26 said:

@BE6Pony

I believe most manuals in the past couple years do that to improve gas mileage. If you watch the A/F ratio when you let off the gas in gear you'll see it go to 20.0 which is as high as it goes meaning all air and no fuel. Maybe 1 out 100 times the fuel wouldn't cut off, no jerk would happen, and the A/F would be normal (14.0) for me. So I figured out that jerk was from the fuel cut off and I'm guessing the driveline tenses up or something because it's being forced to turn your crank. The jerk is from fuel being shut on and off, why it's jerking cause off that is me guessing.

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Good to know, wish I could take that out somehow I don't care that much about MPG.

My 2015 Auto 5.0 does this too. It actually got really bad recently. Interestingly I took the sound tube off my CAI and capped it off and now it doesn’t seem to jerk much anymore.
I think the fuel cutoff thing you are talking about is in all of the cars. I’d bet it is coded into the ECU.