does it have any problem when cold? How many Km's has the car done? Like it is hitting the limiter? My car had a similar problem at one point around 40 000km mark. When accelerating hard it would be like it hit limiter and the tacho would sometimes jump around like crazy even at 3000rpm, it would also miss and carry on when hot, sometimes when cold anyway after about a month of trying to figure it out a light came on the dash i took it into work and got it put on the nissan consult, i had a code for the O2 senor (which has main effect when car is hot) so i replaced it and problem fixed. In short your problem maybe the O2 sensor starting to fail? maybe?? just a suggestion hope it helps