Repair manual for Lexus ES 300 - 1997 Lexus ES 300

SOURCE: 92 lexus es300 knock sensor

Need to remove the upper and lower air intake manifold.  There are two knock sensors for the front and rear pistons banks.  If you plan to do this yourself it is about 1 to 2 hours.  While you are at it, there is a short coolant bypass hose sitting in the same spot, replace it.  Another problem with the knock sensor is the wire harness used to connect the two knock sensors into one connection sometimes wears out and contacts the metal on the engine causing false signals to the ECM, so replace this cable also.
Just did this last summer on my 99 ES300.  Pretty easy.
DIYr

SOURCE: 1999 Lexus - ES 300 - STalling Problem

First of all, change the Lexus Dealership who is doing your rigid maintenance because they are ripping you off and not doing the work or careless on the way out of your engine compartment.
At 95k, you should have changed out your timing belt, replace all the sparkplugs, cleaned out the throttle body, cleaned the MAF sensors, replace the O2 sensors, inspected and replace the fuel rails, and the spark distribution units and you should not be getting a simple problem as this.
All this said, open you hood and look for a vacuum hose that is disconnected.  Most of the hoses which will cause this type of problem is located around the air filter box or connected to that side of the engine.

SOURCE: How many O2 sensors on a 1997 Lexus ES 300?

according to the manual i have... it has three.... one in the exhaust manifold.... and two in the exhaust pipe..... slightly vauge on the exact location of the last two sensors... but looks like it is after the catylitic converter.

SOURCE: 99 lexus es 300 chk engine and trac lock lite on

I had check engine light and TRAC OFF. OBD-II MIL code was P1133 which is Air Fuel Ratio Sensor Response Malfunction and scanned by AutoZone. After disconnecting the battery for 10-15 minutes, the lights went off. I cleaned the gas cap and tightened it firmly. For the last 400 miles, the lights have not come back. When scanning using Snap-on one, no code was detected. I think gas cap was the reason for the lights.

SOURCE: how to replace third brake light on 1997 lexus es 300

"To get access to the 3rd brake light:

- Place each hand against both sides of the plastic housing, and firmly grasp and pull the housing towards you. It might not budge at first, but it should move once you get a good grip on it.

- Pull the housing out just enough so that you can see the brake light bulb and stick your hand underneath. Ignore the speaker wires.

- Pull out the old bulb from the socket (it plugs in/out). Wear rubber gloves when handling the new bulb, and put the new one into the socket.

- Reverse the steps here to put the 3rd brake light back into place. Test out your brake light, and you're done" quoted from lexusk8 @ clublexus.com (great forum)