If your engine is actually knocking and at the same time the KS is also malfunctioning (usually caused by a wiring connection that's loose or corroded), the ECM doesn't then wouldn't/doesn't know of the knock and systems will not compensate for this, so replacing or fixing the knock or its wiring (moreover knowing for sure the KS is functioning properly) is essential to avoiding damage and wasting gas.
Installing a new KS shouldn't help with your issue of focus, so long as you're certain your KS is working fine. FYI - Don't let any mechanic try and tell you a KS cannot be tested in-place on the vehicle (w-key "on", assure 2.5V to 5V is supplied to the KS's core wire, that and assure good ground resistance is measured between the other wire and the engine block).
My knock sensor went bad on my '97 Pathfinder and rather than tear the engine apart (ref. Your $600, my $900) to replace the old KS, I opted to spend about $50 total for a new KS and stub harness which I spliced onto my existing harness and simply bolted the new KS onto the manifold (I left in place the now abandoned KS and it's portion of unused wiring).
My engine runs smoother, has more power and improved mpg.
Serious Note - w/today's adulterated gasolines, ie; carbon buildup results on valves and piston heads, the latter carbon deposit frequently causes the ignited spark to bounce off the piston head at the same time as cylinder fires and instead of a single explosion in the cylinder. Two smaller ones occur, that is until someone runs some good fuel/injector cleaner through the system (assuring that a tank of "premium" gas is run with the cleaner) and when done, often significantly improves power and smoother idling.
Friday, July 20th, 2012 AT 2:52 AM