Hi ya'll just wondering and looking for advice on this topic, I purchased an LS430 2001 at 130k miles about a year ago and have put about 9k on it since today. taken on a long road trip in between them miles with 0 issues.
recently when backing up and putting it into drive the car will rev up but not catch until i force the pedal down and it catches into drive (you can feel it) once it does that it has no issues shifting and drives beautifully only when the car is turned on from off have I had this issue
it's sporadic though, I've went as far as dropping the pan replacing the filter & fluid. didn't make much of a difference at all. I did have an amp that was draining the battery and the first time I noticed this was when I left it on and it barely cranked on and threw it into reverse and drive. I've since replaced the battery (today) and will see if it continues. If anyone has any similar experiences please let me know. If this is a battery issue then i'll be damned! problem is it's beyond sproadic. so only time will tell. a little afraid to take it in because of how random it is & how long it will take to diagnose, I've checked codes nothing. but that damn gas cap.
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I can tell you about 15 years ago that happened to me and Lexus could not figure out what it was and I took it to a transmission shop and they checked it out completely and could not get it to mess up. I finally figured it out myself and it was the battery. The mirrors and steering wheel motors were enough to lower the voltage to the point the computer did not like it. This computer has to have a good clean voltage to operate properly. It has never happened since. I even know of someone that traded in there car to Lexus because they couldn't find the problem and like you said it was sporadic in happening. Guarantee you it is the battery.

 

Also check that this ground wire is good as it helps the car with having good clean voltage: https://www.clublexus.com/forums/ls-...ound-wire.html

 

Forgot to update this, a new battery fixed this issue. instantly haven't had an issue since. kind of wild.