Searched on here and a few other sites. My car is idling fine at the second hash mark above zero (400-500 rpm in drive at stop) and at around 650-700rpm in park or with a/c on. Every now and then the idle will drop to first hash mark above zero and the car just doesnt feel....right.

Going to be cleaning throttle body this weekend and have seen many sites saying to take throttle completely off. For our cars (1997 SC400) do we remove entire throttle body or just spray cleanser onto rag/toothbrush and clean with tb still on and while opening valve?
Any tips would be greatly appreciated and any success stories as well to see if this process is necessary and worthwhile

Thank you and have a great day guys

 

check this
how to clean the throttle body 1990-1994 lexus ls400
this car is same motor

 

^ No link in above post...

Anyway, you can mostly clean the TB with it still mounted, but it's tough to get in there all the way. But, I don't see why the TB would be the cause of occasional idle droop, as the throttle plate is closed then and the IAC Valve bypass controls the air flow.

 

Clean your IACV as well.

 

time spent wondering on pulling the throttle body is time that could have been spent on cleaning the throttle body.

 

Just did this recently on my 97 SC4, yes remove the whole throttle body to get to the other side and clean the intake manifold mine was dirty with thick carbon build up! It was complete night and day difference after cleaning!

As for the IACV ours is a bit different to remove then the others I have seen on early models and DIY's on here.

 

sorry t2d2 check this clud (LEXLS.com)the ultimate in ls400 DIY in this you see this tutorial ok