Knock sensor problem... weird

[Kameko]

ok so i got a engine light when i was doing about 80 on the highway, nothing seems wrong, the car idles fine, it start up fine, nothing is wrong, so i went home and checked the ecu code, it turned out that it was the knock sensor (code 34), so heres my question, i looked around and did some search.. people always say that their car runs rough at idle when their knock sensor is messed, but my car idles fine at 1000rpm everytime i start my car, what is the problem? do i just go ahead and check the sensor and the harness? in another topic, i read that ecu will throw this code sometimes for no reason, is that true?? By the way my car is a 97 240sx with around 90k, please help. thanks

[Mysterfier]

96 240 I have the same prob 125000 miles knock sensor code but car runs great my came on after i changed my exhaust cat back 2.5 in pipe

[Kameko]

mine came after i installed intake...

[mr.zenki]

hmm.... i thought knock sensor doesnt throw CEL. i remember one time i got the CEL on, i checked the ECU and it read knock sensor, front O2 sensor. After i replaced the O2 sensor, the CEL went off but i double check the ECU again, the knock sensor code still flashes. i read somewhere, someone said the same thing, knock sensor doesnt throw CEL. but i have a 95 s14. even thought the knock sensor is bad but my car idles @ 800rpm and pulling fine from 60 - 110mph with no problem at all.