Nissan Repair: Faulty Knock Sensor, nissan bluebird, timing curve

Question
I have a 1995 Nissan Bluebird (Altima). Thankfully, my automatic transmission related problems were corrected by a previous posting. My only remaining concern is that the ECU has been consistently reporting a faulty knock sensor. I have read quite a lot on the subject, perhaps not enough, as I am still confused about whether I should worry about fixing the problem? Is the engine permanently retarded if the ECU sees the knock sensor as faulty?; Or is there a lack of necessary retard due to a faulty knock sensor? I usually use the cheapest (non ethanol) fuel.

Answer
John,

The knock sensor is vital to correct ignition timing and if it is defective the computer will run a pre-programmed timing curve that is pretty conservative.  The computer does this to make sure there is no spark knock.  Spark knock causes rod bearing damage so it is important to have a functioning knock sensor.  If you can live with the bad mileage leave the knock sensor alone.  But, you are probably getting five or more miles less a gallon with the timing not working.  If it were me I would replace the knock sensor as soon as possible.