Sherl

I have gotten one of the knock sensor code previously and the way I fixed it was splicing the wire on ECU from the broken sensor and piggy backing to the working sensor of the voltage input. Now I got both the codes in my CEL however the car works perfectly fine. That is no hesitation in shifting or PWR mode.

it can fly like a rocket when I give gas and put in PWR mode and shifts like as it should. This is driving me crazy as last time when I got it, it had hesitation on shifting and worn rev above 2500rpm I think. I was able to feel the mediocre performance before I performed the fix.

Any suggestions what could this be? It is a 98LS400 with 257k miles.

aptoslexus

Yeah. Bad knock sensor. Or bad wiring to the knock sensor. The engine valley is where rats and mice love to nest. Right under the knock sensor wiring. Or bad ECU. You're supposed to get funky performance because when it throws a knock sensor code, the ECU retards the timing. Not sure why yours isn't affected. It should be. Also, the ECU knows what it's looking for and when it doesn't get it, it throws a knock sensor code. It will throw that code if the knock sensor isn't torqued down enough. It will throw that code if you don't use factory knock sensors. I think you're going to have to bite the bullet and buy a couple of new knock sensors. If you're lucky, it's just some chewed wiring and you can return the sensor. In any case, taking off the intake looks tougher than it actually is. It's a 1.5 hour job to pull the intake off. The hardest part is trying to wrestle it off or put it back on, because it's fairly heavy. A buddy to help out will make the job a lot easier. And photograph where all the hoses go. Take pictures of everything before you do anything.

Sherl

I have done the starter on my own. I did replace the previously broken knock sensor and pigtail on the broken one. I'm curious because nothing is affecting the performance or pickup at all. So what might be the cause. I have previously experienced the failed knock sensor symptoms but I'm not seeing any of that other than CEL codes.

aptoslexus

I don't know. Why did you mess with the wiring if you replaced the sensor? It's possible your wiring hack is causing the issue.

Sherl

https://www.clublexus.com/forums/rx-...repair-17.html

This is simple hack. AFAIK knock sensor is required to adjust timing when poor quality fuel/detonation is detected. I always refill at Shell or Costco or Chevron and ONLY 93.
I think it must be knocked wiring in engine bay.