Knock Sensor

I have a 2001 Tahoe that the dealer replaced a knock sensor in Dec 2002. At the time of replaement I had 29k on the trk, now I have 40 K. It seems that its acting up again. The delaer told me that warrenty on replacement parts is 1 yr. 12k miles. I've gone 12800.

Has anyone else had problems with knock sensors? and if you have what did it cost for the dealer to R&R it?

Thanks

My first question would be why do you suspect a bad knock sensor?

Secondly, the knock sensor is not that difficult to replace...there are 2 sensors under the plastic intake. Just remove the manifold and replace the sensor.

The truck is acting the same as it did when the knock sensor went bad before. When I engage the passing gear the truck I hear pinging, the power is not there also.

I'm assuming its the KS again.

Do you know an approx. cost a dealer would charge to replace the KS?

Thanks