This problem has actually occured twice. The first time, it got so bad that the car would stall any time I came to a stop and let the engine fall under 3000 rpms. And there was serious hesitation when I hit the accelerator hard. Had it fixed by a mechanic for about $500. Not more than 1 year later I had the exact same problem. Brought it to a Nissan dealer and had it fixed for $600. Has been about 4 months since and nothing to note.