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The squeaky wheel gets the grease... I suspect that what is happening, has been happening, is that the "DBW" version of the engine/transaxle controlling firmware creates the 1-2 second delay/hesitation just as Toyota has stated, "to protect the drive train". Apparently to which only a few owners, seemingly, are sensitive or their driving habits or patterns expose them to same. The MASSES, on the other hand, are considered more safe overall with the "DBW" version that prevents any significant level of engine compression braking on those front drive wheels but results in the delay/hesitation experience on RARE occasions. So if you complain LOUD enough and/or LONG enough you will most likely get a "legacy" engine/transaxle firmware version, for the RX300 say, from 2003, before DBW. It's likely that the only real shortcoming of the legacy version is ATF overheating and undue clutch wear resulting in premature transaxle failures. Toyota/Lexus may have decided to live with a few of those in order to dampen down their FWD and front torque biased AWD customer's public "out-cry" somewhat. I sincerely believe the only viable long term fix is a variable volume ATF pump as Ford has adopted for the new Edge or even some sort of fluid pressure storage accumulator as was used in the TC system of the early versions of the LS400. But in the meantime I suspect we are about to see a widespread TSB application by Toyota/Lexus that adopts the firmware control technique for automatic transaxles. The firmware technique now being used to prevent a significant level of engine compression braking on a stick shift FWD (or...) vehicles such as the Suzuki SX4 during driver downshifts.

Replace the "plugged up" catalytic converter.

Lexus of Memphis told me that my 91 LS400 was so old they wouldn't replace any one component, only ENTIRE A/C system, because the stress on the other older ones would cause them to fail in short order. I paid $150 to convert it to R-134 and it has worked fine for the past week now. Find an independent A/C service shop and start by asking them for a quote to convert to R-134. Anything over ~$200 then keep looking.

If there some reason, ANY reason, for the engine ECU to "think" the engine HP/Torque production is not up to snuff then it will not use O/D. In O/D the engine will oftentimes be operating right on the cusp of "lugging", knock/ping. Lowest engine frictional contribution, BEST FE, but only "just" barely producing the required HP given the "cruise" roadspeed.

I've had problems with my AC. I bougt the car about 2 months ago. I am sure the it has not been flushed in a while. What efffects does it have on the AC if the car has not been flushed in a while. NONE! Unless the engine coolant is overtemp and even then it's more likely to be overtemp from failure of one, two or all forced air cooling.

Not so sure '94 had them but if it's there it's behind the removeable panel at the top of the inside of the glove box.

Thank you, by the way I thought there were more, maybe under different model years...... All model years from about '99 for Avalon, Camry, ES300, RX0x0, Highlander, Sienna.......

The "latest" news... New, final(??) fix for delay/hesitation. There are a few posts here and there by owners of '07 Avalons that seemingly indicate that Toyota is adopting the same procedure for automatic transaxles that are beginning to be used for FWD and front torque biased AWD vehicles that have a manual transmission. With a manual transmission the driver cannot be restricted from downshifting regardless of roadbed conditions so the new procedure seems to be to rev the engine up to an appropreately higher level to prevent a significantly high, too high, level of engine compression braking on the front wheels when/if the driver inadvertently downshifts in slippery roadbed conditions. Apparently as of '07 the Avalon (TSB for early production) will now downshift upon a full lift throttle event but will rev up the engine simultaneously to prevent or alleviate any significant level of engine compression braking that might otherwise lead to loss of directional control or interfere unduly with the anti-lock braking system. Now, apparently, there will be no need for a 1-2 second DBW engine throttle-up delay to allow time for the transaxle to complete the double shift, up on lift-throttle and then down to accelerate, in QUICK sequence.

At this very moment the industry, and especially Toyota/Lexus, is struggling mightily with/about this very question. That's simply because it is becoming very obvious to the public at large that FWD and front torque biased AWD vehicles have a much lower overall safety factor that their RWD counterparts. Simple. Engine compression braking on the front wheels upon FULL lift-throttle conditions can easily result in sudden loss of control on a slippery roadbed and even worse it can and will, unless abated via a clutch or a quick shift into neutral, interfere with the anti-lock braking system. Follow the evolution of the engine/transaxle control firmware from the early, first, RX300 in'98' to the '01 model, then DBW in the RX330, and now.............. ---------------------------------------------------------------- New, final(??) fix for delay/hesitation. There are a few posts here and there by owners of '07 Avalons that seemingly indicate that Toyota is adopting the same procedure for automatic transaxles that are beginning to be used for FWD and front torque biased AWD vehicles that have a manual transmission. With a manual transmission the driver cannot be restricted from downshifting regardless of roadbed conditions so the new procedure seems to be to rev the engine up to an appropreately higher level to prevent a significantly high, too high, level of engine compression braking on the front wheels when/if the driver inadvertently downshifts in slippery roadbed conditions.

New, final(??) fix for delay/hesitation. There are a few posts here and there by owners of '07 Avalons that seemingly indicate that Toyota is adopting the same procedure for automatic transaxles that are beginning to be used for FWD and front torque biased AWD vehicles that have a manual transmission. With a manual transmission the driver cannot be restricted from downshifting regardless of roadbed conditions so the new procedure seems to be to rev the engine up to an appropreately higher level to prevent a significantly high, too high, level of engine compression braking on the front wheels when/if the driver inadvertently downshifts in slippery roadbed conditions.

On the early LS series, 92 say, the traction "motor" is located right beside the master cylinder. It is virtaully a duplicate, functionally, of the ABS pumpmotor assembly and in later models they were combined. I would have the brake system thoroughly flushed first by a mechanic/techician that knows about the extra brake fluid bleed valves on the ABS pumpmotor assembly and the one on the traction pumpmotor assembly. I had to show/tell the Lexus tech (EXPERT??!!) where they were and how there were to be used on my 92 LS.

How do you know the refrigernat is full...?? The only way I know to check easily is to see how fast the sight glass/guage transitions from CLEAR to bubbles and then back to CLEAR again because the flow becomes full LIQUID refrigerant. Be sure the car has sat running for a long time with the A/C off and then have someone activate the A/C while you watch the sight glass. Before the compressor kicks in the sight glass should be clear and then witin seconds of the compressor engaging you should see bubbles moving through the sight glass tube. Then within a very short time, 2-3 seconds, you should have a solid liquid flow with no bubbles if the system has enough refrigernat. Absent a dye in the refrigernat it is practically impossible to tell the difference between no flow at all and liquid flow so watching the transition period, empty-bubbles-liquid, is the only way to tell. If the refrierant is TOO low the compressor will not engage at all to protect it.

Install a new A/C air filter, its behind the glove box. Memphis or....? I'm in Olive Branch at the moment.

There might be a clue in the fact that you still cannot buy an RX3x0 without the towing package, which INCLUDES an ATF auxilary cooling heat exchanger. ALL option "packages" for '08 include the towing kit. Just how many RX3x0 buyers expect to tow...??

The owners manual for my 2001 AWD RX300 does not call for any transaxle/ATF scheduled maintenance for the life of the vehicle.

Actually, and to be terribly BLUNT, ABS is quite seriously flawed as is implemented in modern day vehicles. It would undoubtedly be best overall, in all severe braking circumstances, if ABS were to only activate if VSC indicates that directional control is being threatened or compromised.

+++++++++++++++++++++++++++++++++++ Oops...!! Even with the reheat/remix/blend door completely closed, as it certainly should be in "max cooling", you will still have some heating of the airflow due to radiant effects from the nearby, CLOSE BY, HOT, 200F, heater core. You can check for how much effect this is having by turning the compressor off and after 10 or 15 minutes turn the blower to low and check the temperature rise of the system airflow against the OAT. By-the-by, the best cooling can be had with the lowest blower speed provided you are in recirculate mode. Air molecules spend more time in the "refrigerator", cooling evaporator, at the lowest blower speed. +++++++++++++++++++++++++++++++++++ You can check and change( if you haven't) the cabin a/c air filter and clean/service your a/c element.Dirty filter leads to dirty air and dirts on the a/c element thus reducing a/c efficiency. The simplest fix, to improve A/C performance dramatically and get better FE, is to go to Home Depot and purchase a water flow shutoff valve to put into the hot water hose to the heater core. Turn off the how water flow and your automatic climate control will still try to use the reheat/remix mode but no airflow heating will result. I am curious if you have tried this and if it works well. My understanding has always been that the A/C is always pumping air cooled by the same amount and the temp is maintained by re-directing some of the max-cooled air through the heater core. And, of course, the blower speed is also varied. I thought at at max cool setting no max-cooled air is going through the heater core and as the temp reaches the desired point some of the air is re-directed thouugh the heater core which maintains your set temp. Yes, exact description. But, Lexus is "about" .....comfort. In any mode other than MAX COOLING, minimum temperature setpoint, the airflow will NEVER be cool, COLD, enough to discomfort you. This not only results in an exceedingly LONG passenger cabin atmosphere (and materials) cooldown period on a HOT day, it makes the A/C extremely inefficient overall. And yes, I have tried it, sort of... My 92 LS400 has a water flow control valve that is actuated in synchronization with the (reheat/remix) blend door. I guess the LEXUS beancounters got control before the RX series came along. Oh, and don't forget to take the system out of recirculate long enough to purge the HOTTER atmosphere within the cabin. Then return the system to recirculate. So if the A/C is not able to cool the cabin when set to max cool then the valve will not help being that the air is already bypassing the heater core. I would be interested in trying this but it seems like cabin temp would now go below the set point being that it can't re-route some of the air through the heater core to maintain set temp. The only regulation would be blower speed. Dan, Did you recharge the A/C yourself? Too much freon will cause poor performance.

I would think the best procedure would be to drop the sump pan first and clean the debris from it and then do a complete flush. That way there will be no chance for the debris to be (re)distributed throughout the transaxle during the flush.

You can check and change( if you haven't) the cabin a/c air filter and clean/service your a/c element.Dirty filter leads to dirty air and dirts on the a/c element thus reducing a/c efficiency. The simplest fix, to improve A/C performance dramatically and get better FE, is to go to Home Depot and purchase a water flow shutoff valve to put into the hot water hose to the heater core. Turn off the how water flow and your automatic climate control will still try to use the reheat/remix mode but no airflow heating will result. I am curious if you have tried this and if it works well. My understanding has always been that the A/C is always pumping air cooled by the same amount and the temp is maintained by re-directing some of the max-cooled air through the heater core. And, of course, the blower speed is also varied. I thought at at max cool setting no max-cooled air is going through the heater core and as the temp reaches the desired point some of the air is re-directed thouugh the heater core which maintains your set temp. Yes, exact description. But, Lexus is "about" .....comfort. In any mode other than MAX COOLING, minimum temperature setpoint, the airflow will NEVER be cool, COLD, enough to discomfort you. This not only results in an exceedingly LONG passenger cabin atmosphere (and materials) cooldown period on a HOT day, it makes the A/C extremely inefficient overall. And yes, I have tried it, sort of... My 92 LS400 has a water flow control valve that is actuated in synchronization with the (reheat/remix) blend door. I guess the LEXUS beancounters got control before the RX series came along. Oh, and don't forget to take the system out of recirculate long enough to purge the HOTTER atmosphere within the cabin. Then return the system to recirculate.

Atlanta, HOT Atlanta, summertime....more use of the A/C...?

You can check and change( if you haven't) the cabin a/c air filter and clean/service your a/c element.Dirty filter leads to dirty air and dirts on the a/c element thus reducing a/c efficiency. The simplest fix, to improve A/C performance dramatically and get better FE, is to go to Home Depot and purchase a water flow shutoff valve to put into the hot water hose to the heater core. Turn off the how water flow and your automatic climate control will still try to use the reheat/remix mode but no airflow heating will result.

Since at 40,000 miles my ATF was looking and smelling burned I was suspicious of the PTO oil and checked it. It appeared to be clear and "prestine". The diff'l runs in the same, shares, the ATF with the transaxle but has a separate drain plug.

The O/D lockup clutch is generally not hefty enough for engine torque above normal cruising. The engine/transaxle ECU will ALWAYS disable O/D anytime a substantial level of engine torque is called for so the torque converter torque multiplication factor will be used. Bottom line... Once you're in cruise mode at 120MPH+ the O/D might be used if the wind resistance doesn't require too much engine torque to sustain the (whatever) speed. It doesn't matter if you disable it or no, O/D is always locked out during acceleration.

Did the dealer, by any chance, tell you "which" driver the RX adjusts to..?

Unless the VSC was on alone and/or before the engine check light, YES.