is this the idle control valve causing this?

[zen]

as mentioned before high cold speed idle that takes ages to come down to 650rpm..but that i can live with..

main problem (again) is on a run (even a short one of 4miles without having to stop at 50mph) the tick over will drop to near stall speed/will stall (200rpm?)when one does have to stop (lift off throttle.)it will stay at low tickover for ages or untill one turns off engine and restarts (even straight away.)

is this the idle valve playing up??i ask as mine dont seem to be repairable like the mk1 1uz-fe is..(its totally sealed,no 3 srews to undo, 1995 model) and the only way to check seems to be to buy a new one (ouch!espically if its not that!)

 

[Thermactor]

'95 LS400s had an ECU issue that caused idle and stalling problems. It was solved by an updated ECU.

 

[zen]

u sure?if so info please (just incase,but i think it is valve sticking)

 

[lexdud]

I just recently had a very similar issue with my '93 SC400 with 52K miles. The car would start/run ONLY if you gave it some gas. If you released the gas it would die. I took the car to the Lexus dealer and was told that it was a bad IACV and possibly a bad ECU ($695 + $1,500). I bought some used parts off the Net and replaced the IACV ... still no idle. I then replaced the ECU and now it works wonderfully ... all for about $300.

What model do you own? You are right about the -20 IACV as it is not rebuildable (vice the -10).