I would clean the mounting for the knock sensor so that is grounded well. I would clear the codes after a good tune up as well. Usually the knock sensor is triggered by a rough idle or misfiring spark plug. It is rather easy to change the sensor but I would wait until it is malfunctioning.
i have done a full tuneup many times. the code is there even after i erase the codes it comes right back. the only problems i have with my car is a slight whezing noise sometimes when i step on the gas.
My '97 Altima (127k miles) has the Check Engine light on. I brought it for an inspection at the dealership. They said the code was P0304. They said I needed a new intake manifold gasket and PCV valve. I changed the PCV and the light is still on. I live in the Philly area and emission testing is required in addition to the inspection. This state testing is an automatic failure if the check engine light is on.
The stealer wanted $800 to change the intake gasket. Has anyone had their intake manifold gasket go? Is there any "goop" that can seal the "leak"? Can I reset the ECM to get the light to go off? The gasket replacement look like a bear to do myself.
The car runs rough at idle but other than that it's fine. Any help is appreciated. Thanks.