Ticking noise plus CEL came on?

Ok my car has a ticking noise at certain rpms, Which i think its lifter tap. Now i noticed that the CEL came on the other day while driving home. and it pulled a code for the knock sensor. What could this be the result of? My car is a 91 eclipse gst, stock turbo, 3 in. turbo back, hardpiping, greddy profec b, and a few other mods. The noise is only noticeable at around 3k and i only really can hear it in 1st and 2nd, otherwise the wind drowns it out. So its not real loud. Could this be the knock its picking up?

Doesn't sound like lifter tick. I might be wrong but I believe the knock sensor is to far away from the head to pick up valvetrain noise. Try and listen and see if you can tell where the sound is coming from. In my 95 gs-t i could here the lifters ticking at idle and you could tell it was coming from the upper half of the engine.