Question about 1999 Lexus RX 300

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99lexus rx 300! Replaced 2 knock sensors and harness,2 cats,tranny flush, bosch platinum plugs, not iridium!! 11.2 litres Hwy,14.2 city Full tank of gas at $1.08 litre, 341k,not good ! Any insight!!

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Get rid of those Bosch garbage plugs to begin with, put in denso or ngk, like it came with from the factory. Also I would consider replacing the oxygen sensors, as they have more to do with fuel economy than knock sensors do. If you do replace the oxygen sensors, again, use the denso brand, as that is what it came with from the factory and is designed for that car.

Posted on Feb 01, 2017


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Run the fault codes to determine if there are any sensors operating out of set parameters
your indications are that the HO2S sensors are not operating correctly or cannot set the ECM for the air/fuel ratio
could be a problem MAP/Baro sensor, faulty injectors (spraying and not atomizing), low fuel pressure or simply at 17 years old or a guestimate Klm of around 340,000 klms the motor is a bit tired
anyway run the fault codes first and then having a wet and dry compression test ( a qualified service mechanic will know what I mean) done will determine the engine condition

Posted on Feb 01, 2017


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Posted on Jan 02, 2017

Jonah Oneal

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SOURCE: Very high fuel consumption on 2002 Honda Odyssey

transmission slipping dragging brakes.timing off worn timing belt .bad spark plugs + wires +coil.defected valves and worn cam shaft.use scanner to check oxygen sensor. run engine 5 minutes look at scanner . should read closed loop . if read open loop replace oxygen sensor.

Posted on Apr 03, 2009


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SOURCE: 6.5 litre diesel engine, blowing lots of black

my 1995, 6.5 diesel turbo just shuts off when running

Posted on Dec 21, 2009


  • 1 Answer

SOURCE: location of knock sensor and if there are 2 on a

yes,it has 2 of them and they are under the intake manifold

Posted on Jan 09, 2010


Alexander Mimun

  • 3092 Answers

SOURCE: replace knock sensor on 2001 chevy 4.8

You have two knock sensor's, both sit under the in-take magifold on top of the engine, you will have to remove injector rail and in-take.

Posted on Apr 13, 2010


  • 486 Answers

SOURCE: 2003 Chevy Suburban, 5.3 litre ;knock sensor light

I don't have a actual cost for you but it takes about 2.6 hours to do the job and the sensors are usually about $60.00 each. I use the OEM sensors as I've had the best luck with them.

Posted on Jun 15, 2010

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I recently bought a 2000 lexus rx 300> check engine light came on and i was locked out of overdrive< knock sensors and wiring harness with oxygen sensor replaced for !000. now check engine...

I had the same problem with my RX. Had both knock sensors replaced and the problem went away. Be sure to take it to a Tech that has a good scan tool so he can pull the codes and narrow down the problem, From what I understand a constant check engine light is usually not a big deal probably a sensor but a blinking light means major trouble. Take it to a shop that specializes in Toyota and Lexus.

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What is the real cause for the engine alarm to come on stating "knock sensor, bank 2" when one cannot hear the engine knocking?

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Jun 12, 2009 | 2000 Lexus RX 300

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What is the cost of a 90000 mile service for a Lexus RX 300?


timing belt
idler pulley
water pump
timing belt tensioner
valve cam gasket
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spark plug
oil change
pcv valve
tranny oil change
differential fluid cahnge
drive belt
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brake system flush
air filter

good luck,i hope this help pls dont forget to rate me thanks

Jun 05, 2009 | 2001 Lexus RX 300

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