Tried to find my answer on here but haven't found anything quite like mine.... Just noticed this happening while I was in traffic (good'ol california traffic). Anyway, while in traffic and accelerating, staying in first gear (AT), I let off the gas to slow down and the tach goes from 2000rpm down to 1500 steadily, then drops to 900rpm dratically, then bounces back up to 1100 and bounces around their for a second, then becomes steady. Not hearing any unusual engine sounds or reving sounds coming from the motor....so I'm not sure if this is electrical or vacuum related....please help!

 

Mine does this in first as well in tip. It acts as if it's down shifting, but it's already in first. I've never thought this was a problem or anything.

 

According to a mechanic friend at Infiniti there is a software flash that can fix it. I am looking into it :-) thanks!

 

I think it's just the automatic transmission being an automatic transmission. May have something to do with the torque converter. Mine does it as well.

 

^ Agreed...about the auto being an auto that is.