I have a check engine light on for knock sensors,will this make my truck run crappy or in limp mode ? Even though its tuned with HPtuners and while scanning it picks up no knock to where it would be taking away timing ?

 

Knock sensor codes will make it not run correctly thats for sure. Depending on what the code is, the knock sensor might not even be reading anything and thats why you see nothing. But I'm only guessing there, so you should figure out the problem and repair it.