1995 nissan wont go above 2000 rpms help?

i have a 1995 nissan maxima that was sitting for a lil under a year before i bought it. it runs fine and shifts perfectly until it gets to 2000rpms it jerks wildly and then acts like its not getting gas at all. ive checked a whole list of things including air and fuel filter, most of the sensors including the MAF, plugs and wires, and nothing has changed im at my wits end can someone please help.