monarch

Yes, stay alive so you can come home and fill your Lexus with the oil you defended:IRAQ'S PIPELINE TO CALIFORNIA Iraq has historically been a big supplier of California's crude, accounting for one fifth of all the state's imports in 2002. The spigot was cut when the United States invaded Iraq in March, but it was restored in August. -- Sources of oil in California Foreign imports 30.3% Domestic 69.7%. -- Sources of foreign oil imports Iraq 20.1% Saudia Arabia 19.5% Ecuador 13.7% Mexico 8.4% Angola 8.3% Argentina 7.3% Yemen 3.7% Australia 3.5% Others 15.4% Source: California Energy Commission

Could be way overdue for a new fuel filter, air filter, spark plugs, distributor caps, distributor rotors, spark plug wires and oxygen sensor. Could also need a throttle body cleaning and a change of transmission fluid using Toyota Type T-IV.

You're right - I forgot there is one pre cat sensor per exhaust manifold on the V6.

There is only one oxygen sensor you need to replace - it's the one in front of the catalytic converter. If you go to this website http://tinyurl.com/njqgt and type in "oxygen sensor" in the space for keyword, you'll see a new front sensor for a Federal emission ES like yours is about $114.00 with free delivery via UPS Ground This genuine Toyota sensor will look and fit perfectly, just like the factory original one and will last just as long. And after front sensor replacement, fuel economy should improve noticably. The rear sensor (behind the catalytic converter) should last many more years before it needs to be replaced. Beware the sensors available from aftermarket websites like oxygensensors.com may not be identical in every respect so the functionality, reliability and durability of the sensor may not be as good either. The aftermarket websites also provide generic replacement advice rather than Toyota specific advice, so that's why they will say you need to replace the rear sensor too. Also beware some people will likely say you could buy a "universal" sensor for only about $70 from aftermarket websites (or $23 on ebay) and that using a universal sensor will not compromise functionality, reliability and durability. But then they will tell you that to install a universal sensor one needs to solder, splice, heat shrink, crimp, tape, etc. 3-4 wires. So who knows how long a home made wire job using hardware store electical supplies will stand up to summer heat, winter cold, fog, flooding rains, road dust, road debris, etc ??

nc211, on your way northwest up to Santa Barbara, on highway 101, you'll see more Lexus's and Infiniti's on the road that you have probably ever seen anywhere else in the USA before, particularly around the ritzi towns of Calabasas, Thousand Oaks, Westlake Village, etc. Or, if you take the coast highway #1 to Santa Barbara, you'll also see Lexus's and maybe Lamborghini's and Ferrari's around the movie star towns of Malibu and Pacific Palisades. In Santa Barbara Lexus's and Porsches are very popular At Lexus.com I think you'll see there are over one dozen Lexus dealers in the Los Angeles area.

According to Consumer Reports, a near new LS400 filled with conventional oil, factory filters, facotry spark plugs, etc. gets 30 MPG on level ground at a steady 55 MPH. Your particular LS400 probably gets more like 27 MPG at 55 MPH because a number of maintenance items need attention or have been neglected over the years such as the air filter, oxygen sensor, throttle plate, distributor caps and rotors, etc. Expensive K&N filters and synthetic oils not only fail to increase gas mileage (by more than a trivial amount), they also distract car owners from spending time and money on the maintenance items that are causing the cars to get only approx. 27 MPG or so at 55 MPH instead of 30 MPG. So the savvy LS400 owner that's getting 27 MPG @ 55 MPH will spend time and money on certain maintenance items using genuine Toyota parts and procedures that will get the car back up to at least 29 MPG, while the "mechanic in a can" oriented LS400 owner will buy a K&N and synthetic oil and get 27.5 MPG instead of 27.0 MPG.

Compressor and magnetic clutch life can be greatly extended by observing a few rules: 1) Run the AC system at least 5 minutes at least once a week throughout the year, not just in summer. 2) If several days have elapsed since the last time you ran the AC system, turn it on only if the car is at idling speed, not while the engine is spinning fast such as on the freeway. Inside the compressor there are pistons and cylinders just the inside of a car engine and compressor oil drains off critical parts after several days of non operation.

No residual pressure = no residual refrigerant was in the system. There were recent threads on recharging the '91 LS400 and they answer the questions you have posed.

Here are the $23.00 Denso universal oxygen sensors the Ebay seller claims will even work on even the 2003 model Lexus's: http://tinyurl.com/juubn

R134a

The heater should still work in winter even if the air conditioning system is empty of refrigerant. In fact, the air conditioning system (compressor) is designed to stay shut off if the outdoor temperature is below 32 degrees F. The purpose of the engine fan is to PULL cool air from the front of the car through the radiator in order to cool the coolant inside the radiator. The engine fan has nothing to do with the heater.

We discussed this in detail for you two years ago: http://us.lexusownersclub.com/forums/index...opic=10381&st=0

Would you want to buy the cheapest spark plug available? Probably not, because you probably realize how important the spark plugs are for top engine performance and fuel economy. Same thing applies to oxygen sensors.

Use of dyes is not recommended by Toyota because Toyota considers dyes to be a system contaminant that could degrade long term system reliability / durability. Toyota has always recommended use of an electronic refrigerant leak detector or (in the old days) a halide torch leak detector. Dealers and most AC shops have an electronic leak detector. An easy way to prevent refrigerant leaks from ever developing is to simply run the AC system for at least 30 seconds and preferably for 5 minutes or more once every week or two throughout the year, including the winter months.