I've done some searching around, and could not find anything regarding this subject. I apologize in advance if a thread exists.

I'm hoping this is not a costly repair, any insight helps!

In first gear, if the accelerator is pressed too fast/ too far down at once (for spirited driving or a quicker take off from a stop) the car will jolt forward between roughly (1000-1500 rpms) the needle will become stationary accelerate again. This repeats until the car shifts out of 1st gear and it happens only when the accelrator is pressed a little harder than a casual start from a complete start, and it jump anout 500-1000 rpms. If i do not let off the gas the car jolts back and forth as if i was pressing the gas then the brake one right after the other. I explained the situation to many of my friends owning Zs and the only thing we could make out as the possible problem would be the injectors or a trans problem.
Has anyone experienced this and or repaired it?
I'm hoping this is not a costly repair, any insight helps! Thank you in advance for any responses, D