I noticed this problem a couple months ago and thought it might go away once it got warmer, but it hasn’t.
Anytime I start the car and go without letting it get completely warm, the car has a noticeable stumble under mild-medium acceleration. At WOT, the stumble is unnoticeable.
If I start the car and let it completely warm up in the driveway before I leave, the stumble does not occur. Also, the stumble only happens when the car is under load. If I’m stopped with the clutch in and just run the rpms up…no stumble
Any help would be awesome, thanks in advance.
--Cory

 

I'm surprised it's taken you so long to have this symptom. I assume you have a 2000. My car normally does this when cold. I call it "bucking."

The problem is a result of the switchover to the composite IM. The gasket shrinks when cold and allows air to leak into the IM causing the motor to run lean. When the motor warms up, the gasket expands and prevents air from leaning the motor out.

I assume this is your problem but I could be wrong.

 

I actually have a 2001 model (the one in my sig). The IM gasket shrinking? Huh?

I thought it maybe had something to do with closed/open loop operation.

 

This applies to the '00s. Not sure about the '01s.

http://forums.maxima.org/4617018-post28.html

EDIT: Oh and I have sigs deactivated FT?

 

I have the same problem. My car is an 01 i30

 

If you think it's an IM gasket leak you should be able to easily verify.

Buy some throttle body cleaner. Start the cold car and spray around the entire manifold gasket area. If you have a leak the engines tone will change when it sucks in the cleaner. The car might actually start choking and try to stall.

A spray bottle with water also works, but the result will not be a dramtic. The water will actually seal the lake and make things wither smooth out or increase the RPMs.