Is it possible for a knock sensor to be bad and be pulling timing without setting a "Check Engine Light"... I been trying to figure why my truck has turned into a over a progressive period of time. And yesterday the truck just completely fell on its face and the light came on and behold: knock sensor 2 low output. So could it have been going bad the whole time and just now got bad enough to throw a code

 

So, is this a HEMI swap Silverado?

(prolly get more help in the GM tuning section)

 

It sounds like a definite possibility.. Any time your vehicle falls on its face and gets a check engine light, they are probably related. I would replace that sensor (which you should replace either way considering that it set a light) and see if that takes care of your "sluggishness".

but yeah, like mike said, better to post this in the gm section if this is the truck from your sig..

 

i moved your thread for you...

 

The check engine light will only turn on if the knock sensors have had re-occuring errors in the last 4-5 consecutive engine cycles i believe. Chances are they have bit the dirt.

Highly recomended that you change BOTH of them out and the wiring harness. Im not sure of the part number for the harness or what it takes to replace it (I didn't replace mine and im having issues again). Any one know the part number or where to buy the knock sensor harness?