Check engine light? Knock sensors will not do that or even set the check engine light. Some one checked the engine codes what were they? Ingnition primary codes p1320 means one of the 6 coils may be bad replace the spark plugs while your in there Platinum NGK plugs last almost 90 thousand miles. Knock sensor code P0325 does not effect emissions and is just stored in memory. I reccomend a knock sensor for my customers that insist using the low grade fuel.