no power need some help.. ?

[beans33]

Hey, my ca isnt running up to its potential i think. I have a s15 bbt28 on it and stock sidemount and all factory piping. When driving it , it doesnt feel like theres any power until almost 4000 rpms, my freinds n/a ka keeps up with me . there are two codes on the ecu: knock sensor and mafs. My mafs lets me rev jsut fine but does that mean its working properly ? Im to the point i dont know what to do now. Any kind of help is appreciated thanks....

[F3600]

well if you knock sensor is bad you Ecu Retard the timing .. its normal that is not running right .. try to change your maf.. and knock sensor.. after that if the problem is still there you need to look in the wiring. Is your Knock Sensor is wired correctly ?