Bucking in second gear
 

Hi all I have the 6 speed manual and I'm experiencing horrible bucking or jumping in 2nd gear around 4k rpms. Feels like when you first learning to drive stick and have a bad shift. All other gears are fine. Anyone have any ideas?

small update I can get through 2nd gear if I do a very very light accel. In Florida it has been extremely humid/rainy/all around wet the past few days and that's when I first noticed this. Thanks in advance everyone

First Do you have check engine light?
Have you scanned the OBDII for pending codes.?
What year is the car?
How many miles?
Any modifications?
Any recent work done on the car?
When was the last time you changed or looked at the plugs?
When was the last time you looked at the coil packs?

When you say the car bucks your not giving us any information that helps diagnose the issue.
The fact that it just started doing it when the weather changed to humid and wet says look at your coil packs for cracks.

When you say the car bucks what do you mean???
Is the engine misfiring???
If it is you should get at least flashing CEL light and possibly a code.

Hey sorry for forgetting all the extra info I wrote that at almost 4am. No CEL, No codes (haven't checked the durametric yet). 2004 102k miles. Mods: Vivid Racing Tune, catless headers, testpipes, circuitwerks muffler, k&n oil filter, high flow air filter. Recently put the stock throttle body back in the car after having a larger one in 1500 miles ago, Mobil 1 oil change about 2k miles ago, AOS 7k miles ago, Beru coils/spark plugs 8k miles ago. It feels like when your first learning to drive stick and don't have smooth shifts yet. No misfires.

Very very difficult to diagnose issues on cars with mods like yours especially when you have a "tune involved"

Even more difficult over the internet.

If it only happens in one gear then I would look to transmission issues before engine issues.
Also if you get no codes no check engine light.
And you say it is like first learning to drive when you don't have smooth shifting down.
I would look to transmission issues first.

I would take it to a shop for an opinion.
Doesn't have to be a Porsche shop just one that has a good reputation.
Get them to take it for a test drive.

Let us know what happens

I had the motor mount bushing replaced in mine last week and it shifts like butter smooth. I never realized what it should be like I’m certain the mount was bad when I bought the car. Not saying that’s your problem but I had issues with second gear is why I finally got it done. I had the brake fluid flush at the same time and I have much better response there as well

When it happens do the rpm's go up/down? Sounding like the clutch is slipping. Are you leaking oil at the engine/transmission mating surface? Any record or history of the transmission fluid being replaced?

Questions I would start asking myself are...can you reproduce it, does it happen every time or just sometimes, when did it start happening, what changes/repairs were done in the months prior to it happening, anything else happen around that same time it started, what are the outside conditions when it happens (hot, cold, rain, etc). I would start to make a note of when it happens, conditions of the car, outside, etc so you can start to find a common thread with it...unless you can make it happen every single time.

I THINK (dont quote me on this) but the 6 speeds use a different fluid. I am not even 20% sure of this but at a minimum I would think they use a different amount.

If I'm reading this correctly, your issue is not with shifting? You shift smoothly from first to second gear and then if you lightly accel then all is fine, but if you mash if I the floor you feel the "bucking" around 4k rpm?

If that is correct, your clutch is slipping (as Stl said). How does you clutch pedal feel? Where is the bite point? When these clutches go bad the pedal tends to get very hard and the bite point is higher up along the pedal travel.

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I had something vaguely similar when the transmission mounts gave up on my 924S, so it is worth checking them and the engine mount as suggested earlier. Otherwise I would tend towards a gearbox problem, have a look at the oil to see if there are metal particles.

If I understood the OP's post it only happens in 2ND gear.
So not likely to be a slipping clutch.
If it was it would happen in more then just 2ND gear.
But I have been wrong before.

The reason I figured that was because 2nd gear is quite torque-y (is that a word?) And just about 4k is when you start to see the torque peak. I assumed that it would likely do the same thing in 3rd at work as well. Now that it's daylight though and I'm reading it again, if it's.only in 2md gear and not reproducible in other gears it may be deeper in the gear box. Maybe he is on his way to needing the 2nd gear detent upgrade?

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I had a bit of a clunk going from first to second. As others have mentioned - check your engine mount.