jlc45

Hi everyone,
I have a new-used (2017 with 38k km) IS350AWD. Everything seems good, the car drives well.
My question is regarding idle speed at startup, which seems high. The engine fires right up and idles at about 1400 rpm after an overnight rest. It takes about 2 to 3 minutes to settle down to about 1,000.
I don't want to put the car in gear at 1400 rpm, but the wait seems too long to me. After the car is warmed up it idles properly and this "feature" goes away. Is this normal? Can the idle speed be adjusted so that it settles down more quickly? Thanks.

arentz07

This would be normal if it's very cold outside (as in, below freezing or something like that) and the car has been sitting for many hours.

I don't know of a way to adjust this. Why do you think it needs adjusted?

Does it really take 2 to 3 minutes in real time? When I lived in Kansas City, in the winters there my IS 300 AWD would idle above 1100 or so for about 30-60 seconds on cold days if it had been sitting outside in 20-30-degree (F) weather.

jlc45

Thanks for your reply.
I am familiar with the topic. I have timed the duration of the issue (fast idle speed) and it is 2 1/2 to three minutes at well over 1000 rpm.
This happens after the car has been sitting overnight, and it's not that cold out. Normal idle is about 750 - 800 rpm.
I don't want to put the car in reverse (or drive) at high idle because it is very hard on the transmission, the driveshafts and the axles.
If this persists I'll get it looked at by the dealer.

jtrue28

It's normal. You won't be able to adjust it.

swaangin

Normal, I would say it's at 1400 for less than 20 seconds, drops down to 1100~1200, that's when I start driving but a few minutes of driving, it'll idle below 1000.