Im experiencing a weird idle issue when my car is in drive, my idle is 400 like literally on the second rpm line, when in reverse its at the normal 700-850 sometimes its a little low like high 600s. When my car is in park the idle is about 750-950 and when in neutral the readings are similar to those of the reverse rpm. Also when my idle is low like that my steering wheel gets heavier and i swear toward the very end of the turn radius it feels kinda clunky/choppy. when my a/c is on my drive rpm raises to about 600-750. ive replaced my MAF, cleaned my throttle body, new air filter, so just maintenance to see if it was under maintained, but idk what it could be any help/suggestions? I had also had a bad vacuum leak and i replaced a lot of hoses/evap stuff , but the issue got worst after i just recently replaced my old serpentine belt due to noises and thats when the rpms really started to drop.

 

Have you cleaned the throttle body and holes for the air mix path?

 

Yes/no, i cleaned the main throttle body hole, but I didnt even know these little ones were there lol, will a carbon cleaner work? and do i just shoot it in there from under the pcv valve, or shoiuld i take my intake boot off and try to remove the tb?

 

This is not about a LS430 but the technique for a Celsior/LS400 98-00 will help and guide you.
The upper link in Japanese is my original post and the lower link is the English version by a gentleman LS400fanboy.
https://minkara.carview.co.jp/userid...0193/note.aspx
https://www.clublexus.com/forums/ls-...ttle-body.html

 

Hey, so i found where it was, cleaned it up, and my car feels way better now, and my idle is at 600 so hopefully that was it, ima further research those air mixture paths that run through the plenum though and see what would be an efficient way to clean them, thank you so much, this was a really big stress on my chestand ifeel way better and i think my car does to, wish you a good night thanks again.

 

You are welcome. Now you know how the additional air is sent to injectors.

The best way to clean is to remove all injectors and clean them professionally but this is not an easy job and I suggest you to try a simpler way to clean the path all the way from the entrance of 2 bigger holes to injectors. After spraying a carbon cleaner enough to those 2, using an air compressor and apply a compressed air to those but the pressure should not be exceeded 0.25Mpa. Too much pressure may damage injectors. It would be preferred to try a couple of times or more if the cleanness was not sufficient and not getting the stable idle speed.

 

If it hasn't been done, consider changing your PCV valve as these over time can get stuck open. Also there's a large breather hose connected to the plastic intake box which goes to the right side valve cover and those have a tendency to become brittle and crack, but it's hard to tell when covered by the box. Also check your VCV for the charcoal canister which is mounted to the upper left hand side of the intake.