how can u tell if ur knock sensor is bad?...i know ur engine light would come on...but my light stays on because i have no egr valve...is it possible you can tell if its bad by the way the car runs...i mean i have a little hesitation on the take off...but i think its from not having an egr valve and also by having a 1 and a half inch header with down pipe that goes out to an 2 and a half inch catback exhaust...i effed up and bought those cheap azz chinese headers from e-bay which im changing to stillens in 2 weeks...any info will surely help...thanks

You can check it for resistance. It's basically a microphone. Are there any other codes besides EGR?