Road Trip!

[Power Pack]

Just back from 3,700 mile trip from OR. thru ID, WY. CO. N.M. and back.

'04 RX330 is a great trip vehicle but engine and gear ratios are set up for EPA ratings not reality driving.

When this car sniffs a hill it downshifts to 4th. and if on Cruise Control will often downshift to 3rd. in an effort to maintain set speed.

Also, high winds on flat roads in Wyoming will cause downshifts. I have taken to kicking off cruise, slapping lever to 4th. and driving like a stick shift without a clutch. Car actually gets better gas mileage between 75 and 85 then 65 to 75 because engine is in a better torque range.

Wyoming wind blew off a big piece of exterior window trim! Quality?

Power Pack ('98 GS400)

Eugene, OR.

[GDixon]

My recent trip was 3.400 miles from Northern CA through Yellowstone NP, Glacier NP, and return through WA and your OR. This was in an 08 RX 350 and it did the same frequent downshifting at high speed. The point is that Lexus must be satisfied with that quirk in the car since it still exists with the 2008 model that has plenty of HP to handle slight lugging. The head mechanic at a Lexus dealer said that the transmission has two overdrives so cycling through all three of the "D" gears is a usual issue.

The worst is when going up a hill and every 2-3 seconds it decides to lurch into another gear. It does not make for pleasant or peaceful driving. For some reason, the constant shifting is hard to get used to and is startling when it occurs.

I ended up leaving the cruise control off and tried to feather the throttle just enough so the downshifts would not occur. Speed was lost on hills but it is a fair price to pay for not being constantly jerked around. Your solution sounds similar.

As Clinton might say, "I feel your pain." ;)

[Power Pack]

My recent trip was 3.400 miles from Northern CA through Yellowstone NP, Glacier NP, and return through WA and your OR. This was in an 08 RX 350 and it did the same frequent downshifting at high speed. The point is that Lexus must be satisfied with that quirk in the car since it still exists with the 2008 model that has plenty of HP to handle slight lugging. The head mechanic at a Lexus dealer said that the transmission has two overdrives so cycling through all three of the "D" gears is a usual issue.

The worst is when going up a hill and every 2-3 seconds it decides to lurch into another gear. It does not make for pleasant or peaceful driving. For some reason, the constant shifting is hard to get used to and is startling when it occurs.

I ended up leaving the cruise control off and tried to feather the throttle just enough so the downshifts would not occur. Speed was lost on hills but it is a fair price to pay for not being constantly jerked around. Your solution sounds similar.

As Clinton might say, "I feel your pain." ;)

Thanks for your reply. I sometimes wonder if RX owners are just passive about the performance aspect of their cars. The '04 RX330 is my wifes daily driver and she's getting tired of all the drama involved in operating this car. Our other car, (mine) is a '98 GS400 with 150,000 miles on it, still perfect and goes like the wind. I know that I'm spoiled! "Wouldn't you rather have a V8"?

Love the Clinton line.

Thanks, Bob S.

[Camski]

Downshifting while going downhill without cruise control is a bit odd.

However, downshifting in cruise control to maintain speed is normal as the box is designed to shift down to provide engine braking (that's why now many BMW's have auto braking cruise control and many other car makers have the laser guided cruise control).

Slightly rough between gears but that's acceptable considering the cars weight, power output and 'only' 5 speed box. Other than that it's all good here at my end.

[Power Pack]

Downshifting while going downhill without cruise control is a bit odd.

However, downshifting in cruise control to maintain speed is normal as the box is designed to shift down to provide engine braking (that's why now many BMW's have auto braking cruise control and many other car makers have the laser guided cruise control).

Slightly rough between gears but that's acceptable considering the cars weight, power output and 'only' 5 speed box. Other than that it's all good here at my end.

Thank You.

"Bob's Yur Uncle"

Bob S.

Eugene, Oregon

U.S. of A.

[GordonB]

My recent trip was 3.400 miles from Northern CA through Yellowstone NP, Glacier NP, and return through WA and your OR. This was in an 08 RX 350 and it did the same frequent downshifting at high speed. The point is that Lexus must be satisfied with that quirk in the car since it still exists with the 2008 model that has plenty of HP to handle slight lugging. The head mechanic at a Lexus dealer said that the transmission has two overdrives so cycling through all three of the "D" gears is a usual issue.

The worst is when going up a hill and every 2-3 seconds it decides to lurch into another gear. It does not make for pleasant or peaceful driving. For some reason, the constant shifting is hard to get used to and is startling when it occurs.

I ended up leaving the cruise control off and tried to feather the throttle just enough so the downshifts would not occur. Speed was lost on hills but it is a fair price to pay for not being constantly jerked around. Your solution sounds similar.

As Clinton might say, "I feel your pain." ;)

I just joined this forum in search of information on the very problem that you are describing. My new RX350 bothers me the most in slower traffic situations by downshifting and giving the appearance of a slipping transmission. This car only has 3000 miles on it, and I have already taken it back to the dealership with this complaint. The mechanic did acknowledge the problem on a test drive, and then told me that it was a normal function. He described the transmission as a "Learning Transmission", and said it would get used to my driving characteristics after a while. He also acknowleged that the ES350 has the same transmission, and does the same thing.

If anyone out there reading this forum has had the same problem, or knows of any fixes, please let me know

Thanks,

Gordon Fish

Sandpoint, ID

[wwest]

My recent trip was 3.400 miles from Northern CA through Yellowstone NP, Glacier NP, and return through WA and your OR. This was in an 08 RX 350 and it did the same frequent downshifting at high speed. The point is that Lexus must be satisfied with that quirk in the car since it still exists with the 2008 model that has plenty of HP to handle slight lugging. The head mechanic at a Lexus dealer said that the transmission has two overdrives so cycling through all three of the "D" gears is a usual issue.

The worst is when going up a hill and every 2-3 seconds it decides to lurch into another gear. It does not make for pleasant or peaceful driving. For some reason, the constant shifting is hard to get used to and is startling when it occurs.

I ended up leaving the cruise control off and tried to feather the throttle just enough so the downshifts would not occur. Speed was lost on hills but it is a fair price to pay for not being constantly jerked around. Your solution sounds similar.

As Clinton might say, "I feel your pain." ;)

I just joined this forum in search of information on the very problem that you are describing. My new RX350 bothers me the most in slower traffic situations by downshifting and giving the appearance of a slipping transmission. This car only has 3000 miles on it, and I have already taken it back to the dealership with this complaint. The mechanic did acknowledge the problem on a test drive, and then told me that it was a normal function. He described the transmission as a "Learning Transmission", and said it would get used to my driving characteristics after a while. He also acknowleged that the ES350 has the same transmission, and does the same thing.

If anyone out there reading this forum has had the same problem, or knows of any fixes, please let me know

Thanks,

Gordon Fish

Sandpoint, ID

An explanation: Google for:

wwest abolition

and/or

wwest hesitation dbw

[SeaDuck79]

Hey, I've complained before about the stupidest cruise control ever on my '04 330. If it detects the slightest loss of torque, it downshifts, and there goes your MPG. Even on a freeway overpass, it often downshifts. Going faster does help, but at anything under 65, I usually leave it off.

Why a quality brand with top engineers like Lexus would put such a crappy part on their vehicles is beyond me. I drive lots of cheaper rentals from all different mfgrs, and NO other car I've ever driven is like that.

Lexus: FIX IT if you expect me to buy another one someday.

[wwest]

Hey, I've complained before about the stupidest cruise control ever on my '04 330. If it detects the slightest loss of torque, it downshifts, and there goes your MPG. Even on a freeway overpass, it often downshifts. Going faster does help, but at anything under 65, I usually leave it off.

Why a quality brand with top engineers like Lexus would put such a crappy part on their vehicles is beyond me. I drive lots of cheaper rentals from all different mfgrs, and NO other car I've ever driven is like that.

Lexus: FIX IT if you expect me to buy another one someday.

When "you" are driving you are able to see the "future", roadway conditions which might require a bit more gas, etc.

On the other hand the cruise control drives "blindly" into the future and therefore doesn't "realize" an incline in the roadway has been reached. But the cruise control does have some "prediction" capability to compensate. It's goal is to attain/maintain a FIXED speed so it can compute and select EXACTLY the most correct, highest, gear ratio to maintain that speed provided conditions are not outside the "norm". The cruise control also has the ability to change the ignition timing to slightly "slow" the vehicle on a downhill run. That seemingly, takes us to 18 (see below) "gearbox" ratios.

That always results in a more abrupt, noticeable, action by the cruise control than would happen with human vision in use.

Add that to the fact that these new cars use the O/D lockup clutch in 2 or even 3 of the top ratios means they have as many an 9 forward gear ratios to select from for CVT emulation (best FE) and you end up with one "busy" gearbox. It's even possible, concieveable in my mind, that cruise control has more gear ratios available, automatically (exclusive of the ignition timing caoability), than do you.

The core, base, problem is that you purchased a significantly OVER-powered vehicle and thus the engine, even at an exceptionally low RPM, can produce enough, just barely enough, torque to move the vehicle along fairly briskly in cruise mode right on the cusp of lugging vs not. And that's the "place" to run that engine for best FE but then even a minor "pertubation".

Pity the trucker with an 18 speed manual gearbox and Diesel at $6.00.

[wwest]

"FIX IT..."

You could do that yourself by forcing an advance in ignition timing or leaning of the A/F mixture anytime the engine is under load, normal crusing load, and the RPM is below ~2500. That would result in engine ping/knock below that RPM and then the shift "map" would be automatically modified by the engine/transaxle ECU to avoid gear ratios that would result in knock/ping.

But the FE would go "south", perhaps dramatically so.

[grouch]

Glad you had a comfortable trip. I had a shorter trip to the OR coast and back. We had to stop every 100 miles to get the feeling back into our butts from the hard seats. That was two months ago and I still can't sit on a hard seat for very long.

[wwest]

Hey, I've complained before about the stupidest cruise control ever on my '04 330. If it detects the slightest loss of torque, it downshifts, and there goes your MPG. Even on a freeway overpass, it often downshifts. Going faster does help, but at anything under 65, I usually leave it off.

Why a quality brand with top engineers like Lexus would put such a crappy part on their vehicles is beyond me. I drive lots of cheaper rentals from all different mfgrs, and NO other car I've ever driven is like that.

Lexus: FIX IT if you expect me to buy another one someday.

Just for your information both of the 2007 rental cars, Chrysler Sebring and Mazda minivan, I drove on vacation in fairly flat HI in the early spring of '07 simply could not decide which gear to use, continuous "hunting", cruise control or no.