I have a 93 sc300 5speed with 110,000 miles that when it sits for a few hours and I start it up the RPMs go up to 1600. I have to wait about 4 minutes for it to drop to normal at 700 rpms before driving it. The rpms are normal during everyday driving. It's only when it sits for hours, including overnight, that the rpms go high but come down after about 4 minutes of waiting. It's been doing this for about a week now. I had it tuned about a month ago with new spark plugs. Any suggestions will be appreciated. Thanks... Gville.

 

Its normal. Its just cold so it idles high and when it warms it goes down to normal.

 

sounds normal to me.. well.. hopefully thats normal.. haha.. cause mine does the same thing..

 

With the intake air temperature is low and the engine oil is cold, the car will idle higher to warm up the car faster. 1600rpm is a very normal idle on a cold engine in cold weather. Do not worry.

 

mine idles at 1200 hah.. n i drive off at 1000.. not passing 2k till the temp needle gets close to mid.

 

Mine does the same but at 2000rpm. Stays longer on colder mornings. I just drive off when the ecu dips the throttle from 2000rpms to 1500rpms and keep the revs low until I feel hot air in the cabin

 

just wondering is there a way to change the idle? i know Hondas u can adjust the trottle cable.. but can you do that to Lexus? im just wondering.

 

I got the same problem and have 2 treads running and still dont have a solution. Mine started about 2 months ago. I have checked vacum hoses changed O2 sensors. I am at a loss. from what I am reading it varies some cold idle is 1200 or 1500. It should be no more that that. The oil has to curculate within the motor and reach the head. I see this wearing the engine over time. Today I am going to recheck all vacum line to just make sure I didnt miss anything