Where is a good place to route a wire from the engine compartment to the passenger side foot well? I'm trying to connect my new Knock Sensor to the ECU. Guess I could use an existing wire but I can't find one from the ECU and the knock sensor.
Mine is a 2001 RX300

 

What's wrong with the existing knock sensor connector?

 

I've put a knock sensor ont op of the intake manifold so I need to connect it to the ECU. So far I haven't had any luck locating either of the two wires connecting the existing knock sensors to the ECU. Locating these wires where they connect to the knock sensor harness would be the ideal setup but no luck yet.

 

Just look for the harness coming out from under the intake manifold on the driver side. That's the knock sensor harness. It leads to a connector roughly under and to the left of the throttle body.
That connector leads straight to the ECU. So maybe the easiest thing to do is buy the knock sensor harness, connect your new sensor to it, disconnect the old harness at the connector, and connect the new harness.

This guy did what you are doing. Here's the knock sensor connector: