1999 Lexus rx300. New knock sensors, harness,etc. when I start it,it knocks ,has no power,very sluggish.

code p 0330 refers to knock sensor (KS)2 bank 2 ---circuit malfunction===causes wiring--KS---ECM
it is possible that in changing the harness there is a problem connection or the connection to ks2 is not correct ( not on properly)

You have 2 of them,here's a link showing where their at,once you get to page,click on switch and relay. SENSOR KNOCK CONTROL 176 07 Fits LEXUS RX300 1993 2005 Part 8961512090... Here's a video showing you where they are at. 2000 Lexus Es300 Knock Sensor Location Repair

Here's a link on replacing your knock sensor. RX300 knock sensor replacement DIY Club Lexus Forums

RX300 Mega Thread. Start here if you have a problem - Club Lexus ...

www.clublexus.com/.../679100-rx300-mega-thread-start-here-if-you-ha...
Feb 17, 2013 - One question per post please. ... manual-search, just enter RX300 or whatever Lexus vehicle and year ... Side affects of CEL: Based on the error code, your RX may end up in a .... You may hear a drop in rpm of the donor car. Window Switch Problems Pass side
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knock sensors are significant sensors for timing advance. if the engine is knocking then the computer will retard the timing thinking that it is pinging and you can lose well over 50% power. sometimes the sensor picks up other vibrations and creates timing problems even if the engine itself is not at fault.

P0330 = "knock sensor no.2 circuit malfunction (bank 2)." This sensor is on the bank of cylinders which contain cylinder No.2. Either the sensor is bad or the wiring to the sensor is bad. The knock sensor detects when pre-ignition (pinging or knocking) is occurring and tells the computer. The computer then retards the ignition timing to prevent engine damage.

The 1999-2003 Lexus RX300 models have a common failure of the engine computer that causes the harsh shifting of the transmission. You need to get the computer (ECM - Engine Control Module) rebuilt or replaced before it causes permanent damage to the transmission. Even if the transmission is already ruined, the ECM will still need to be repaired. Most often, the transmission is fine though, and rebuilding the ECM will restore the smooth shifts that the Lexus should have. Circuit Board Medics can rebuild the ECM and reprogram it so that you only have to plug it back in when you get it back. See the link below:

http://circuitboardmedics.com/1999-2003-lexus-rx300-hard-transmission-shifting-ecm-ecu-computer-repair/

I'm not a lexus guy , but I'm thinking that you have a vacuum leak somewhere.

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

knock sensor needs replace