I'm not intimately familiar with the V8 cars, but I understand the generalities of troubleshooting the knock sensor.

You can easily check the knock sensors IF your car is such that you can put on a timing light. With some of the newer ignitions with individual coils you can't put on a timing light.

The basic is that if you hit the block with a hammer in the general area of the knock sensor, you should see the timing retard. This is easy to test on engines where you can indeed use a timing light.

Hope this helps,