Could be the coil breaking down. I heard that the 2.5's had this problem at some point. Any Check engine light?
If not, then check the throttle body is clean, check the TPS, Lazy 02 sensor.
With such little mileage I wouldn't think the injectors were dirty just yet.
Take it to the dealer, for sure.
This could be poor fuel, as well as a part problem.
Any codes [engine light] thrown?
A dealer can scan for hidden codes that do not appear on the dash.
It could be SO many things, even a reflash of the computer may be the service bulletin fix.
"They all do that!"(j/k)
Take it to the dealer and also get a dealer print-out of the complaint and results for your records if warranty work is needed out-of-warranty later. I got a TB cleaning and a new IAC valve this way. Start a log to keep track of patterns.
There were some catalytic converter issues with earlier cars, most problems fixed by '07.
I've still heard of some engine replacements in the Sentra because of it. Get it checked out ASAP.
I previously owned a Spec V. Those things are a blast!
Thanks for the ideas guys---no check engine light, I didn't realize codes could be stored without a check engine light being illuminated. I'm hoping for something easily identifiable and simple to rectify, maybe a TSB like MechTech mentioned for a simple computer reflash or something similar 'cause I really love the car except for the annoying hesitation/bucking at times that really bothers me. Other than that the car really is a blast to drive, great engine/transmission/suspension/structure. Thanks again guys!
Update: Took it in to the dealer, of course it ran fine when I took the Technician for a ride, they checked for codes and did a diagnostic "self-scan" and everything was fine so they had nothing more to offer. It's still doing it from time to time, I guess I'll have to wait until it activates the check engine light and logs a code, the tech said without a code and it only occurring intermittently it can be very difficult to find out what's wrong.
Thanks StevieC, you're right, it is frustrating because the car is a blast to drive otherwise, thanks for the words of encouragement, never thought I'd see the day where I was actually hoping for a check engine light to come on!!
I hear you... It's not fun and especially for us that know something isn't right with our vehicles... I'm hearing a weird noise when I turn my wheel leaving parking spots coming from the driver side wheel.
I put it up on the jack and my and my dad (mechanic) had a look at it and we can't determine what it is at this time so I'm gonna keep driving it the way it is until it gets bad enough that an obvious part is the problem.
I hit some road kill last week and I think it damaged something, but we can't pinpoint the noise and the car has to be rolling to make it so it makes it impossible to duplicate in the driveway with the wheel off.
Hang in there...