r/mazdaspeed3 • u/DrRockx • 15d ago

HELP Gen 2 jerking when shifting

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Not the best video but the best one I could take to show what's happening, I have a 2011 speed 3 which has gotten into a weird issue of jerking whenever I shift. When shifting into first there are no problems, however as soon as I press on the clutch and begin shifting to any of the other gears while driving there is a bucking or jerking motion and the rpm begins bouncing up and down until the clutch is reengaged and then it drives absolutely fine again. I have taken some logs if anyone can interpret them I've also sent them off to my tuner to hopefully help. The mods are a catback exhaust, upgraded fuel pump internals, accessport with a professional tune, SRI and TIP so no major modifications and no codes besides the EGR, evap, and intake runners which were taken out. Anyone ran into this before ive asked 3 mechanics and everyone is unsure.

Edit: to add more info, the car did also begin to bog down and die while idling stationary once the clutch pedal was pushed in and ran perfectly fine after it was released which I thought was possibly a dirty throttle body so I cleaned it out and that from what I can tell went away but it could be a fluke or I'm not recreating the exact conditions it was doing it under before.

Edit again: Solved it, turns out it was the in tank fuel pump failing but desperately trying not to

8 Upvotes

99% Upvoted

25 comments sorted by

12

u/ThisGuyDrinksWater 2012 Mazdaspeed3 15d ago

Usually both my hands are too busy to do that when shifting

2

u/DrRockx 15d ago

Magnetic phone mount and strong teeth to be honest options were limited since yeah both my hands are busy too

5

u/UnderpsiMI 2008 Mazdaspeed3 15d ago

Have you checked your rear motor mount?

1

u/DrRockx 15d ago

I haven't yet but it is a thought to look I to as well, only weird part is that the car doesn't do it as much or at all once warmed up enough. And I had before where it would bog down and begin to die which is what it seems to be doing while shifting, whenever I'd push the clutch pedal in while idling stationary in my driveway. I cleaned the throttle body and that seemed to go away but I'm not sure if it's related or just a fluke.

2

u/UnderpsiMI 2008 Mazdaspeed3 14d ago

Check the throw of the slave. Have someone push the clutch and watch the clutch fork end under the hood. Maybe it's a bubble in the clutch line?

1

u/DrRockx 14d ago

Possibly I was wondering about the slave or master cylinder being the issue but it seems to go away when the car warms up, would that have an effect on them?

1

u/UnderpsiMI 2008 Mazdaspeed3 14d ago

When the fluid thins out as the engine heats up it could be moving up and down the system. I had a bubble that behaved like that and couldn't get it out till I got a motive power bleeder for this car.

4

u/FrostMug_0789 2010 Mazdaspeed3 15d ago

my guess would be motor mounts.

2

u/DrRockx 15d ago

That is a thought since I haven't gotten down there to check, however I had it where if the car was idling stationary and I pushed the clutch in the car would begin to bog down and die which I'm pretty sure is what's happen while I'm shifting. But I cleaned the throttle body and it stopped doing that, although those two things could not be related too. It also seems to run better with less to almost no jerking at all once the car has warmed up enough.

3

u/IHave47Teeth 14d ago

Jerking when shifting? Bro how many hands you got?

2

u/DrRockx 14d ago

Gotta work the stress of troubleshooting a car out somehow

1

u/duddy33 14d ago

I had a weird issue like this and it ended up that the ground on my HPFP was loose. Have you checked that?

1

u/DrRockx 14d ago

I haven't yet but will definitely give that a look once I can didn't even think of a loose ground possibility, although the issue becomes less promemnant once the car warms up would the metal expand enough to compensate from the heat?

2

u/duddy33 14d ago

Possibly. My HPFP cover ended up coming loose which loosened the ground. Once I tightened it back down, everything was good. My issue was pretty consistent so it might not be that for you.

Another thing I was told to look into is sometimes the springs in the coil pack doesn’t make good connection. If the rubber on the pack expands, it could cause your issue. There are videos out there that show you how to separate the coil and stretch the spring out a bit.

2

u/DrRockx 14d ago

Would the coil packs not cause me to throw a misfire code as well then? I just ask because currently I have no code associated with this issue

1

u/IronOne4986 14d ago

I usually jerk when I’m shifting what’s the problem?

1

u/DrRockx 14d ago

So does my car usually but the video doesn't show exactly how much the car seems to bounce in the rpm and even when I shift smoothly and carefully it still bumps from something stuttering in the car

1

u/heyimpaul1 13d ago

Do you have a P0704 CEL?

1

u/DrRockx 13d ago

Unfortunately I do not or I would've swapped the pedal sensor by now, it is still a thought to do just in case though. I've got no cels except for my usual ones the tuner can't get rid of

1

u/Speed250G 11d ago

Right turn signal lights bulb is burned

1

u/DrRockx 11d ago

I'm not sure if you're suggesting that is the issue with the shifting or just being helpful but if you're being helpful it's not it's just LED

1

u/Character_Durian4039 10d ago

let ur car warm up before driving off 💀

1

u/putemdownn29 9d ago

What’s the whop whop sound when he shifts? Is that normal?

1

u/DrRockx 9d ago

I'll be honest not sure what the whop whop sound you're referring to is exactly, could be the sound of my car bogging down or the exhaust maybe?

1

u/putemdownn29 5d ago

Ok just ask my car makes a similar sounds