idle RPM "stability" ?

[victor_t]

It's a new car for me, so please excuse all the stupid questions :)

most of the time my idle RPM is constant at ~750RPM (sometimes 1000 when the engine is cold)

but from time to time when I am at a light waiting for it to turn green, I notice the RPM needle moving around 750. I don't hear any bad noises from the engine and the movement is not violent, but I notice that it's not sitting at constant 750 as it usually does.

Is this normal?

[Donutz]

Yes. I believe Sas covered this off before. Something about the computer switching from open loop to close loop.

[sas]

I see, I’m becoming a history. Yes, I mentioned this, it was thread with the big floating range.The small variations are allowable. At IDLE, the engine has a small power, just to compensate friction. Any load changes ,battery charging , conditioner ,steering pump, can to cause the rpm changing. Plus, the fuel trim changing and work of purge valve are noticeable too.

[Flagrum_3]

It's a new car for me, so please excuse all the stupid questions :)

most of the time my idle RPM is constant at ~750RPM (sometimes 1000 when the engine is cold)

but from time to time when I am at a light waiting for it to turn green, I notice the RPM needle moving around 750. I don't hear any bad noises from the engine and the movement is not violent, but I notice that it's not sitting at constant 750 as it usually does.

Is this normal?

Like the others said, yes it seems to be normal.If and when you experience it again, just give the throttle a light tap and it will steady the idle out.That's what I've found anyways.


_3