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Unless you rewire the fog circuit so you can use fogs independent of LB why not just leave them off?

Didn't have much choice. Our dealer (Lexus of Bellevue) said that all of the 330s shipped to the NorthWest were all AWD. Certainly all I saw on their lot were. I don't mind - makes the spousal unit feel better about driving in inclement weather. ← There are ways you can make an RX300 more truly an AWD vehicle, even rear torque biased. First, install ~1.5 wheel spacers all around so you can use snowchains at the rear first and then also at the front as required. The spacers also allowed me to upgrade to 17x8 wheels and use Bridgestone Turanza 235/65-17 summer tires. I never hesitate to throw on at least one set of snowchains if the weather, and these NW drivers, dictate. So I run summer tires year 'round for quietness. If you want a true AWD RX300 you can remove the transaxle mounted diff'l case, open the center diff'l case, remove most of the spider gearing and weld the rear drive spider gear into place. Now you will have a good solid mechanical coupling to the rear driveline and the existing viscous coupling for driving the front if the rears begin to slip severely. Keep in mind that the RX300's viscous coupling fluid is not formulated for a serious level of torque coupling as some are (AWD Chrysler T&C immediately comes to mind), 25% to the front is the best you are likely to get and that only after some serious period of rear drive slippage. Converting the RX330 to rear biased AWD is a bit more difficult but it appears that it can likely can be done by purchasing and installing the Viscous clutch assembly for an RX300.

I would assume that during the day following each disconnect the ECU will be "busy" re-learning the engine/transaxle parametric mapping. So the "safe" thing to do insofar as this test is concerned is to "reset" to the factory default parameters each night.

"Why even make an AWD?" Does the statement "One born every minute" suffice?

Fogs are H3 H4 is dual filament for high/low beam combined.

They would not have to worry about the new, factory fresh non-driven cars, only the demos, or ones that have been driven enough for the ECU to have "learned" how lean the mixture can be throughout the engine's RPM and loading parameters.

Can some one who is really, REALLY encountering this problem do me a favor? Each night for say a week or ten days disconnect the battery for about 10 or 15 minutes. The engine/transaxle ECU will be forced to revert to the default factory parameters for fuel mixture and that may eliminate the engine hesitation symptom. At least until the ECU can re-learn just how much it can lean out the mixture before the onset of knocking/pinging and I doubt that one day would be enough. You don't suppose that's what the dealers do each night so new customers never encounter the symptom??

What is your definition of warm?? The Lexus climate control, absent being in max cooling, uses a reheat/remix method wherein ALL of the system airflow is first chilled via passing through a COLD A/C evaporator and then a selected portion (ALL, in the case of max heating) is diverted through the heater to be reheated. Both portions are then remixed resulting in air outflow that is not so cold as to be discomforting but still cool enough to eventually cool the cabin down to the temperature setpoint. As the cabin reaches your temperature setpoint the system airflow, in cooling mode, will sometimes be only about 2F below the setpoint. This effect will be even more pronounced if the solar radiation sensor(s )(at the bottom of the windshield near the defroster ducts) are not exposed to bright sunlight. Personally when I am traveling in the South, or any area of HOT climate, I turn these automatic climate control systems to MAX COOLING and then use the blower speed to adjust/keep the system to/at my comfort level. The efficiency of the A/C is increased dramatically via this method resulting in fewer compressor cycles, lower heat loading on the engine cooling radiator and increased fuel economy.

The bulb itself is not amber, it has an amber glass cover/filter and a metal mask for beam pattern formation/shading.

The RX300's version of AWD isn't. The engine torque in the AWD version of the RX300 is heavily biased to the front, 90/10 F/R, and over an extended perior of front wheel slippage the viscous coupling will "tighten" up and change the ratio to as much as 75/25 F/R. This statement and numbers were confirmed on a four wheel dynamometer. So a FWD RX300 equipped with VSC/Trac etc, is likely just as good in the snow as any AWD RX300. The AWD RX330 is even worse.

Actually I signed up for that when it first became available but quickly discovered that they don't have anything like "theory of operation" pertaining to their own unique design aspects. Everything otherwise is available in the model specific shop manuals I purchase whenever I buy a new Toyota or Lexus.

And yet another clue... It has bothered me a bit that Toyota and Lexus are recommending that premium fuel will alleviate some of the problems of engine hesitation. Even more bothersome is the fact that some posters have stated that going to premium fuel was helpful in alleviating the symptoms. WHY? So I first went to my 2001 RX300 shop manual to read up on the knock sensor and how it was used. Other than the obvious I found no new information there. But the knot on my head was still festering and I couldn't stop scratching it. So yesterday out of curiosity I dug into the 2004 RX330 shop manuals regarding the use of the knock sensor. Surprise...! My RX300 uses a RESONANT knock sensor and the RX330 uses a NON-RESONANT knock sensor. The difference?? The resonant knock sensor in my RX300 has a fairly narrow response bandwidth and due to its resonant charactoristics cannot easily be used to discern a fairly light, non-serious, engine knock or ping from a more heavy knock/ping that can quickly result in serious engine damage. On the other hand the RX330's non-resonant sensor can be used to sense a wide bandwidth of engine knock/ping "sounds" and can readily discern light levels of knock/ping from more serious ones. What this means is that the RX330's engine/transaxle ECU can "push" the fuel/air mixture ratio "envelope" even further into the regions of engine knock resulting from a "leaner" mixture without unduly incurring potential engine damage. The ECU can "trial run" various lean mixture ratios at all ranges of engine RPM and loading and detect the onset of engine knock/ping before the knock/pinging level is serious. The RESONANT sensor in my RX300 is like a stall warning in an airplane, no indication of just how serious the situation really is, might be. So the newer Toyota/Lexus models equipped with the non-resonant sensor would be able to operate the engine throughout its full RPM and loading ranges much, much closer to the "twilight zone", area of potential damage from predetonation, than would my RX300. That would, or course, result in the need for greater care, resolution and sensitivity, in selecting the proper gear ratio for a given throttle position commanded by the gas pedal.

THis may be helpful here.......... Someone on another thread asked why their Lexus feels like the cruise control is "punching it", when only a small increment in roadspeed needs to be regained. "Punching it...." Remember that the automatic transmission/transaxle is heavily biased toward wanting to be in O/D, with the lockup clutch engaged, in order to achieve the best possible fuel economy. If any level of additional torque is required of the drivetrain the lockup clutch must be quickly released in order to bring the torque multiplication aspect of the torque converter into play. And again, to help achieve the best fuel economy under acceleration. So even the slightest additional throttle opening will often result in the transmission/transaxle ECU commanding a downshift out of O/D. Also keep in mind that even absent being in O/D modern day engines are running right on the "cusp", the leanest fuel/air mixture ratio possible using the downstream oxygen sensor for long term, slow reacting, feedback and the engine knock sensors for instantaneous feedback when the mixture gets too lean, the timing too early, or the engine is "lugging". Engine knock or pinging can pretty severely damage an engine if not quickly corrected or if allowed to often occur even on an intermittent basis. Engines knock or ping because the fuel/air mixture "flamefront" is expanding too rapidly for the cylinder volume or in the alternative the piston itself cannot move downward as fast as possible to accomodate the rapidly expanding flamefront. The latter is typically the result of "lugging" the engine. Most of us who often/still drive stick shifts know by experience and instinct to downshift a manual transmission before we get into the "lugging" range of the engine. But what about modern day automatic transaxles/transmissions...?? They LEARN. Over time, as you drive the car, the engine/transmissaxle ECU will build a "map" of parameters which it then uses to avoid engine operational circumstances that are detrimental. The ECU literally "wants" to achieve the absolute best in fuel economy but not at the detriment of mechanical failure of the drivetrain, short (knock/pinging) or long (transmissaxle clutch wear) term. Think about what happens if you fuel a car that requires premium fuel with regular. The ECU detects pinging in some areas of the previously learned and stored parametric mapping and adusts, accordingly, the operational charactoristics, parameter mapping, of the engine ignition timing, Fuel/air mixture vs RPM & loading, and transmission shift points. But that's the simple part... How does it know to re-adjust all of those parameters once you refuel with premium? Because it pushes the fuel economy "envelope", continuously! In order to continuously, ALWAYS, operate with the very best parametric mapping for the best fuel economy it continues to "experiment" with the parameters. So, not long after you refuel with preimum "it" will have discovered that the previous, more conservative parameters are no longer valid and build a new set.

"Punching it...." Remember that the automatic transmission/transaxle is heavily biased toward wanting to be in O/D, with the lockup clutch engaged, in order to achieve the best possible fuel economy. If any level of additional torque is required of the drivetrain the lockup clutch must be quickly released in order to bring the torque multiplication aspect of the torque converter into play. And again, to help achieve the best fuel economy under acceleration. So even the slightest additional throttle opening will often result in the transmission/transaxle ECU commanding a downshift out of O/D. Also keep in mind that even absent being in O/D modern day engines are running right on the "cusp", the leanest fuel/air mixture ratio possible using the downstream oxygen sensor for long term, slow reacting, feedback and the engine knock sensors for instantaneous feedback when the mixture gets too lean, the timing too early, or the engine is "lugging". Engine knock or pinging can pretty severely damage an engine if not quickly corrected or if allowed to often occur even on an intermittent basis. Engines knock or ping because the fuel/air mixture "flamefront" is expanding too rapidly for the cylinder volume or in the alternative the piston itself cannot move downward as fast as possible to accomodate the rapidly expanding flamefront. The latter is typically the result of "lugging" the engine. Most of us who often/still drive stick shifts know by experience and instinct to downshift a manual transmission before we get into the "lugging" range of the engine. But what about modern day automatic transaxles/transmissions...?? They LEARN. Over time, as you drive the car, the engine/transmissaxle ECU will build a "map" of parameters which it then uses to avoid engine operational circumstances that are detrimental. The ECU literally "wants" to achieve the absolute best in fuel economy but not at the detriment of mechanical failure of the drivetrain, short (knock/pinging) or long (transmissaxle clutch wear) term. Think about what happens if you fuel a car that requires premium fuel with regular. The ECU detects pinging in some areas of the previously learned and stored parametric mapping and adusts, accordingly, the operational charactoristics, parameter mapping, of the engine ignition timing, Fuel/air mixture vs RPM & loading, and transmission shift points. But that's the simple part... How does it know to re-adjust all of those parameters once you refuel with premium? Because it pushes the fuel economy "envelope", continuously! In order to continuously, ALWAYS, operate with the very best parametric mapping for the best fuel economy it continues to "experiment" with the parameters. So, not long after you refuel with preimum "it" will have discovered that the previous, more conservative parameters are no longer valid and build a new set.

Many times... The most common failure of starter motors is the commutator brushes and so the most common overhaul is a cleanup and brush replacement.

4. Owners/drivers who rest their left foot on the brake pedal. Even the slightest pressure on the brake pedal will result in the pads being continuously in contact with the rotor and thereby continuously HEATING said rotor. Watch the traffic ahead of you on the freeway for the number of high-mounted brake lights on with the vehicle obviously in "cruise" mode. My 2001 AWD RX300 is showing no sign of brake warpage at close to 50,000 miles nor did my 2000 RX when I traded it in. I would NEVER, have never, hesitated having my rotors turned, "cut" if needed and within tolerance.

Okay, lessons.... 1. The fog lamp assembly, lens and reflectors, are designed to have the beam pattern LOW and wide. 2. A heavy or even slight amber shading will enhance your forward vision, object definition in rain or fog. 3. Fog lamps are best used alone without the visual interference resulting from BRIGHT/WHITE low beams being simultaneously. Additionally I find that when the fog lights are on with low beams on a clear night the CLOSE in illumination of the surrounding landscape results in my eyes reacting and reducing my vision. So it is not a good idea to have those fogs on when there is no fog or rain. I rewired the fog circuit on my 2001 RX300 so I can turn the fog lamps on without low beams. Most european cars come so equipped.

I found that on the earlier LS model Trac can be used as a good forewarning of a slippery roadbed but a light "learned" foot on the gas pedal will get you up and going much more readily than a trac system that instantly dethrottles the engine upon drive wheel slippage. Later models delay the onset of engine dethrottling to allow the driver to have more control in modulating the gas pedal.

My searches, google, etc, seem to turn you a predominance of transaxle downshift caused hesitation complaints across multiple marques vs VERY few RWD transmissions. Can you refer me to a few?

The Rx300's premature transaxle failures are the result of the need to downshift upon acceleration but without adequate hydraulic pressure present. So the engine developes acceleration torque quickly (the gas pedla is mechanically coupled to the throttle butterfly) and the the downshift clutches slip initially due to the lack of high pressure to force them fully and firmly engaged. This appears to occur in the range of 70,000 to 80,000 miles at the earliest. And I have come to believe that since toyota is well aware of the problem there exists an unspoken warranty policy to cover these early failures. But do make him aware of the propensity of the climate control system to suddenly fog over the interior surface of the windshield in these vehicles. Google for demist defog & denso for more on this.

Actually my only real complaint about the 2000 MY GS300 we owned briefly was the SURGE you got with just a slight bit of throttle application. It was especially sensitive, no way to avoid head-snapping acceleration, when starting up from a full stop. After taking up all the backlash I could from the throttle cable I took it in to Lexus where the service manager INSISTED that my car had an e-throttle. Have you seen anything close to the number of complaints of hesitation with RWD as we seem to be seeing with just the FWD Toyota/Lexus marques?

IMMHO the RX330's hesitation problem/symptom is Toyota's "fix" for the premature transaxle failures in the RX300 series. The RX300's engine starts developing high torque the instant you apply (more) pressure to the gas pedal. The RX330's engine doesn't so the transaxle clutches do not slip during downshifting.

Biased....?? NOT! Do we know where gas prices are headed? I cannot believe any sort of demographical research indicated that there was a substantial market for high perfromance SUVs. But what I continue to believe is that Toyota somehow, in some way, boxed themselves into a corner. When the RX400h was initially announced I was so enthusiastic that I went directly to the dealer to put down a deposit. Then the production delays started being announced. After the third one I cancelled my preorder. Why was the atkinson cycle, possibly yielding as much as another 20% in fuel economy, not used in the RX400h? Why is the city fuel economy, while quite good, not better than hwy, as indicated by the EPA estimates? Did Toyota discover, during the R&D phase, that the hybrid synergy drive as implemented in the Prius could not be scaled up to the level required for an RX238?

Hesitation.........RECAP It appears that somewhere about the year 2000, possibly earlier, Toyota made a design change in the ECU control firmware for ALL transaxle, FWD, type automatic transmissions. Basically the modification involved upshifting the transaxles to a higher gear, say O/D, or maybe even into neutral, during coastdown circumstances wherein the gas pedal was fully released. Many owners of the RX300 made note of this aspect, describing it as a feeling of being bumped lightly from behind just before coming to a full stop. At higher coastdown speeds owners described the feeling as the "slingshot effect", the vehicle "apparently" gaining speed upon throttle closure. It is relatively easy to see that this design change would result in improved fuel economy and lower overall emissions. But if that were the real, or core reason, why not apply the same modification to Toyota's RWD based vehicles? Why only the FWD or front biased AWD vehicle models? The only possible answer, seemingly, was to eliminate or substantially reduce the instances of loss of control due to inadvertent, otherwise unavoidable, engine compression braking on, potentially, a very slippery roadbed. And if you browse about here and there on the internet you will find that many RX300 owners are complaining about premature transaxle failures at 70,000 to 80,000 miles. And there is yet another clue. The owners manual for the RX300 series makes not recommendation for ATF flushing and replenishing for the life of the vehicle. Yet at 40,000 miles the ATF in my 2001 AWD RX300 smelled burned and looked more brownish than pink. When I enquired of Lexus corporate about this I was informed that the new recommendation was to drain and replenish the ATF each 15,000 miles of standard usage. WHY? The hip bone is connected to the leg bone! Let's assume that I am correct and my RX300 transaxle quickly shifts into O/D, engaging the lockup clutch. Now when I suddenly decide to accelerate the engine will respond to my gas pedal depression INSTANTLY. The O/D lockup clutch is clearly not designed to withstand strong engine torque, nor is likely the 4th, O/D, clutches within the transaxle. So the transaxle must now be downshifted into the proper gear for acceleration given the current roadspeed, and QUICKLY before the engine starts delivering a really serious level of torque. But the problem is that with the transaxle being configured for coastdown mode with the ECU having commanded LOW transaxle hydraulic pressure and with the engine at low RPM there is insufficient pressure to fully engage the new downshift clutches fully and quickly. So the RX300 transaxle clutches SLIP for a few milliseconds during each of these "unexpected" downshifts. Slipping clutches generate lots of HEAT and frictional surface wear beyond that planned during the design phase. Upon reading some of the posts from owners I have come to suspect that Toyota has instituted an "unspoken" warranty program for otherwise out of warranty transaxle owners with premature failures. So what does Toyota do about these premature transaxle failures? Basically NOTHING! Except for future models. Those get an e-throttle which allows the engineers to delay the onset of engine torque developement long enough for the hydraulic pressure to rise substantially and thereby fully and firmly engage the "downshift" clutches. Why not just eliminate or delay the upshifting? CAFE & CARB regulations. Or The automotive insurance industry has picked up on the fact that FWD vehicles have a significantly higher accident and injury rate during adverse weather conditions that their RWD brotheren. Regardless it has now become pretty obvious that there is no going back insofar as eliminating coastdown upshifts are concerned. And please remember that Toyota is now on record saying that the hesitation symptom is a result of the need to protect the drivetrain.

Contact RH wheels