Lexus Repair: lexus rx300 4x4 p0325, p0330, lexus rx300, sensor wires

Question
i am getting both knock sensor codes from a 99 lexus rx300.  waveforms seem to be normal, except for mesuring hz.  alldata, and snapon both give a spec of 7.1khz, but i am getting a very "dirty" frequency.  another shop replaced the pcm before I got to it. also, the trans will not shift into overdrive, even if the codes are cleared.  if you have a more useable spec, or if you know if I should get a cleaner frequency reading, it would be very helpful.
                        thank you,
                        Collin Graves
                        lead tech, Tunex
                        SLC, ut


Answer
Hello Collin, I am not sure if I can help you on this one. This is not a common problem. I would look at the knock sensor wires and harness at the engine. I have seen where rodents will make nests under the intake and then they will chew on the wires.