I have a question regarding these knock sensors. My 2002 XJ8 does not get a code but does knock slightly when the engine is cold and I am accelerating lightly between 42 and 46 mph. When the car warms up, I don't get the typical knocking, but a rather loud rattling sound. Passengers in the car have asked if something is loose. Has anyone else experienced these rattling sound symptoms and did you ultimately relate it to back knock sensors?

Also, I had a mid 90s Buick and was getting knocking and was told to test the sensor by putting a screwdriver on the sensor and tapping it with a hammer. If the idle did not change it was not a bad sensor. If the idle did change, I had basically tricked the sensor into thinking the engine was knocking and the idle would change. Since I don't know which side might be culprit, I was wondering if anyone knows of this or another test method.

Thanks.

 

Do you know what timing chain tensioners the car has?

 

 

Restricted Performance. Code 332. Knock Sensor Bank 2. Thanks to so many other posts here I found the knock sensor and its connection back to the loom under the thermostat housing. Cause of my problem. Top hose blew off and a gallon and half of steam gave me a spectacular arrival at work. Now that was the easy part, and a fix and refill with the necessary for an English winter had me on my way. However two or three days later I got the fault code above. Cause - not a failed sensor but water ingress into the above mentioned connector. Had to clean it, dry it, twist it, and reconnect twice before the fault was cured. My tip to disconnecting this connector is find the similar one on the loom which is high to the rear of the bay on the (English) passenger side. Practice with a small screwdriver to flip the catch where you can now see clearly. Many thanks to other posters for tips on measuring the sensor resistance and to then avoid disturbing the sensor.