01 Nissan pathfinder check engine light came on with code p1320?

hi i have a 01 nissan pathfinder with a 3.5 liter 5 speed manual. at about 103000 miles i changed the sparks. now at alittle over 104000 my service light came with the code p1320 got it from advance auto parts diagnostics tool. it is a ignition primary circuit fault code. it also said it could be something wrong with ignition or it is a misfire which i think it is. it doesnt even idle right anymore. it seems like it wants to stall. when i accelerate the engine hesitates until about 2000 rpm where doesn do it so much but it still is alittle rough. anything under 2000 rpm it vebrates rumbles. are my coils going bad?? spark plugs bad?? what can it be i don want to take it to nissan and pay more than 500 dollars to fix when i can fix it myself?? i need help