A day or 2 ago my 03 coupe 5AT started bucking a little every once in a while while I was driving, and it felt really weird but I had an inspection scheduled for tomorrow so I decided just to wait for that. Today, it started doing that more often and the tachometer needle was kind of vibrating like it couldn't stay perfectly still while at a steady speed, just enough to notice it nothing big. But also my car stalled once at a red light and almost stalled (the rpms went way down to like 100-200 and sounded like it was going to shut off) a few other times while stopped. I barely got it to my mechanic, but I'm wondering if anyone has any idea about what it could be.

My only engine mod is an Injen cold air intake that was already installed when I bought the car exactly a year ago today...nice anniversary present right?

 

Check the 02 sensors.