Hesitation.....

wwest · November 30, 2004

My Rx300 is an 01 AWD and I am on record as saying the hesitation syndrome does not exist in it. What it does do is shift into "neutral" (for wont of a more descriptive or correct term) during coastdown and/or just before coming to a full stop.

My suspicion about all of this is as follows.

When the Prius was in design phase they decided to eliminate engine lagging torque during "coastdown" in favor of simulating the same "feel" using the battery charging braking regeneration system. Even today the Prius driver can manually select engine lagging torque or battery recharging.

And then via engineering "cross-polination" someone in the FWD design area realized that the same method, eliminating engine "drag" during coastdown by taking the transmission out of gear would result in improved fuel economy. They may have even realized that a side benefit might be fewer loss of control accidents in adverse roadbed conditions due to engine braking on the front drive and STEARING wheels.

I think we have pretty much confirmed that the hesitation issue only applies to Toyota/Lexus FWD models or AWD with front torque bias.

Now, my 01's gas pedal is directly connected to the engine so if I suddenly go WOT while the transmission is not in gear the only design choice they had was to put the thing in gear as quickly as possible.

Sorta like on my 300HP C4 applying WOT and THEN releasing the clutch. Burned smell from the area of the clutch.

My transmission fluid smells and looks burned at only 38k miles, this for a vehicle that has NO factory recommedation for transmission fluid, has a towing package, external transmission fluid cooler, that has never been used. I am seeing reports of transmission failures for my model years between 60k miles and 100k miles.

Anyone want to guess why my Transmission fluid is burned at 38k miles?

So, someone with e-throttle suddenly goes WOT in the same circumstance. The transmission firmware "talks" to the engine and says "wait" I need to get myself into gear and give the transmission clutches and bands an additional few hundred milliseconds to fully seat".

Seems, if true, a problem that could readily fixed in firmware, right?

NOT!

Before even one was shipped these vehicles were EPA qualified for a specific city/hwy fuel economy. What does the EPA say, or do, if the manufacturer, after the fact, wants to go back and revise the fuel economy adversely?

And possibly even more pertainant, what about the PR issue?

Now, I have heard that the hesitation problem in the 05 RX330 has been fixed, and please correct me if I'm wrong, but haven't I seen a posting wherin someone was asking why the MPG rating of the 05 was poorer than the 04 by only a MPG or so?

ColinBarber · November 30, 2004

Anyone want to guess why my Transmission fluid is burned at 38k miles?

The viscous coupling which is causing the fluid to overheat?

I didn't think there was this problem with the FWD RX or the Camry/ES?

SW03ES · December 1, 2004

I think we have pretty much confirmed that the hesitation issue only applies to Toyota/Lexus FWD models or AWD with front torque bias.

If you're talking about the hesitation when applying throttle from start then no, that hesitation exists in RWD Lexus also.

wwest · December 1, 2004

RWD Lexus also...

May I ask where you heard that?

I haven't read or seen any postings regarding experiences with the hesitation problem in RWD vehicles.

SW03ES · December 1, 2004

Ownership, my dad has had two and both have the hesitation. A 98 and now an 04 LS. If you look around in the LS forum there are several threads about the throttle lag. The GS has it too, it was apparent from the first second I drove one. For some reason its DISCUSSED more in the RX and ES circles, I think because more RXs and ESs are sold.

Any Lexus service advisor will tell you every Lexus has this hesitation. Its a function of the particular driver whether they notice it or not.