Should I Replace Air / Fuel Sensor For $550?

[coltonb]

I have a '99 ES 300 that i bought CPO in '01 from Lexus of Manhattan, which now has 112,000 mi. Religious regular oil changes, transmission oil purge, the whole 9 on regular maintainence (non-dealer serviced). Has run beautifully despite the beating i give it (long distances, hard accellerations, and NYC potholes aplenty.)

Couple minor on-going issues: rough idling & occasional stall on start, esp. when A/C is on, and seems to burn oil. (1 QT every 1,000 +/- miles).

Check engine light goes off yesterday- i bring it to dealer today, and they say the fuel/air sensor has failed and needs to be replaced. "Drivable, but you should get this done" they say. I don't remember the exact $# but it was north of $500 to get this replaced.

Is it worth it? Is it related to the on the minor on-going issues?

[steviej]

the rough idle on start up can simply be a dirty idale air control valve and or dirty throttle body. cleaning of these items by yourself is easily done if mechanically inclined.

O2 sensors (fuel/air) do get lazy and even crap out. They are expensive but can be had for less money than physically at the dealerships parts counter. They can also be put in in a matter of minutes (but the dealer will get you with a minimum of 1 hours labor). Did they tell you which one was in need of replacement. Bank 1 Sensor 1, Bank 2 Sensor 1, etc. (your have three). If replacement is necessary, the sensors can be obtained from online Lexus parts dealers for less and can be installed in your driveway if you are mechanically inclined. Running with a bad sensor will only accelerate catilytic converter decay and that is very costly to replace.

Before you replace the sensor, and sk will back me up on this one, seek out a reputable repair shot that can do a "motor vac". This may solve alot of your problems.

As for the oil loss. Are you leaking oil or burning oil? In other words, got spots in the garage/driveway or do you have blue smoke coming out you tail pipe? Check around the the valve covers and other seals in the engine. Do they look "wet" and oily? Lastly, and I have to bring it up, if your engine is starting to sludge, then you may be eligible for an engine replacement under Toyota's sludge warranty if you qualify.

steviej

[coltonb]

Thank you for your insight. As they say, the best answers lead to better questions, so...

where is a good source for sensors?

What does a motor vac accomplish?

I'm burning oil - there is no leakage and everything looks very clean under the hood and under the car. How would I know if my engine is sludging?

[Magata]

I would suggest you examine whether or not you have oil sludge. This model is common to the oil sludge problem that Toyota has admitted. Toyota has extended the warranty time frame and mileage caps so that all the ES, RX, Camry, 4 Runner V6 engines can get their due repair. Good Luck!

[steviej]

where is a good source for sensors?

www.irontoad.com

www.lexus-parts.com

JPI Importz (LOC club sponsor....click on the associated link)

[steviej]

I'm burning oil - there is no leakage and everything looks very clean under the hood and under the car. How would I know if my engine is sludging?

I guess the best way would be to pull the front valve cover and it will be pretty evident if it is sludging.

steviej

[steviej]

What does a motor vac accomplish?

I will leave this to sk to explain completely.

but, as much as I have read and as far as I know, it is a thorough mechanized cleaning of the top part of the engine (air intake, fuel injectors, fuel rail, throttle body, combustion chambers, etc)

From what i have read, they are not that expensive either....maybe a c-note.

steviej

[SKperformance]

Start by getting the engine cheked for engine sludge ,first

since what is the use of fixing things on a dead engine.

there is a huge post that shows the exact happenings of sludge in an ES

A mtorvac is a high pressure cleaning solution where they disconnect the gas tank and run this system through the engine instead.

It cleans all the carbon out of the engine and sensors as well as exhaust.

They also clean the throttle body as well to finish a perfect cleannig job.

Think of it as a high quality descaling for the inside of the engine to improve milage and hp for $100