1999lexusLS400. Drives goog but while driving if u have to accelerate quickly in situations the car only revs and doesn't deliver responsive speed

 

When was the trans oil and filter last serviced?

 

And probably another case of Valvoline max life, yeah it will work for a while, till it messes things up. How many miles on the car, with the right fluid and occasional changes the transmissions out last everything else on the car.

 

I suspect your trans need better fluid as well. use only OEM Toyota type-IV ATF fluid in there!

 

These forums are a wonderful place for information when posters join to share info, experience and resolve their posts with a follow up....unfortunately many first time posters are seeking a fix and will never post again.

I am interested to see if changing the fluid helps to solve the OPs issue.

 

+1. I'm feeling something similar with you, Moarpower.

Regarding the slow response issue for 98-00 models, there are different kinds of symptoms and causes. I have experienced some of those while helping local shop owners and even a dealership. Some of them were related to the solenoid or the ECU while others the throttle body, incorrect ATF and etc. I need some more detailed information from Rnatpenn to give him my advise.

Believe it or not, the initial 98-00 ECU failure often causes the strange AT shift problem and this causes the slow engagement of gears or the shift shock . Most of this can be simply checked by reading the ripple voltage in the FAQ but it doesn't say any about the AT shift. When I wrote it, I haven't had enough experience with the shift issue.