Does anyone know whats up with my car? I am throwing to codes: 1)Knock Sensor and 2)Manifold Absolote Pressure solenoid valve or circuit fault (code 13/02).

Sometimes when i am driving ill be in a lower gear and punch the accelorator, the enging (and tach) will fly, but the car will barely accelerate. I was on a hill today and engaged first gear and barely made it up the hill. I was in 3rd with tack at 6000+ doin 30ish (should be like 90ish).

Can anyone tell me whats up or if this has happened to them and repair costs. A friend asked a nissan mechanic and he never heard of this code before.