I have a 2011 IS350 and have noticed that while sitting at a red light the RPM's will sometimes jump from around 600 - 700 to over a 1000. It even causes me to have to push on the break a little harder to hold it and then when I let off the break it jumps forward. It seems to be worse when the engine is cold. Do these cars sometimes run a higher RPM when cold to get the engine warm?

 

I wares to ask this same question. Mine use to idle higher (800-1000). Now it idles at 600-700 normally while in park.

 

All car idle like that on cold start. Once you drive it for few mins to warm up your rpm will be at 600-700. Depending how cold it's is outside.

 

When its colder the rpm's will be higher. Once the engine gets warm it should drop to to 600-700.

 

warm up your car before driving it

 

lol @ this thread. When the car is < op temp, it will idle higher because the ISC (idle speed controller) causes it to idle a little higher. This is basically how a choke worked on cars with carbs. It does that so fuel doesn't atomize and condense on the cold metal. Because if it did, it would lean out the Air Fuel.

 

hmmm... yeah, it's normal for the engine to idle higher when it's warming up. But I don't think I've ever seen it "jump" when at a stop light, nor have I had to hold on to the brakes any harder. Maybe I just have a heavy brake foot with a weak 250 motor?

Does this only happen when the engine is first starting up?

 

u dont need to warm up cars nowadays

 

the 1950s called, they want their car advice back


The proper way to "warm up" a modern car is to drive it, not let it sit there idling after you start it. Says so right in the owners manual.

Idling is terrible for a car.

 

550rpm

Koz

 

mine is around 600

 

well they cant have it

I dont care what the manual says, when a car wether new or old is first started all the oil is still sitting at the bottom of the pan, I rather give it time to lubricate all components before going forward.


EDIT: usual idle for me is about 700

 

I almost hit a person crossing the street because the rpm's suddenly jumped from like 700-1500. When it's cold my rpm's jump around randomly untill the engine is at operating temp.

 

The "time" it takes for the oil is about 15-30 seconds.

Roughly the time it should take to put on your seatbelt after starting the engine.

Anything after that you're just wasting gas and hurting the engine by idling it.

 

I've known that idling is just a waste of gas, but how does it hurt the engine?