Hunting idle when warm

[Sequence]

Noticed the rpm hunting a bit again today after driving the car for a bit and it has done it both times i had stopped.
Have seen it before a couple weeks ago but generally it does not do it, it is only climbing by around 100-200 rmp and goes back down again this only seems to happen when warm not when cold, no codes logged to give any indication.

Any ideas? has 1700 miles on it.

 

[Jsimba]

Noticed the rpm hunting a bit again today after driving the car for a bit and it has done it both times i had stopped.
Have seen it before a couple weeks ago but generally it does not do it, it is only climbing by around 100-200 rmp and goes back down again this only seems to happen when warm not when cold, no codes logged to give any indication.

Any ideas? has 1700 miles on it.

If it's as you're coming to a stop, are you sure it's not the car creeping? At a complete standstill with the auto handbrake on, my car sits at c.800 RPM. If it's creeping forward or auto handbrake hasn't engaged, RPM is about 100-150 RPM higher, at 900-950 RPM

Sent from my SM-G960F using Tapatalk

 

[Sequence]

If it's as you're coming to a stop, are you sure it's not the car creeping? At a complete standstill with the auto handbrake on, my car sits at c.800 RPM. If it's creeping forward or auto handbrake hasn't engaged, RPM is about 100-150 RPM higher, at 900-950 RPM

Sent from my SM-G960F using Tapatalk

This is stopped in park and electric handbrake on.
will sit at 800rpm for a mo and then rise to 900-1000 and drop again a second or two later will rise again

 

[jebusRS]

is it not to do with the car putting the radiator fan on more, on and off causing the revs to climb slightly? you can hear it when the car is warm if your at the front end.

 

[Sequence]

is it not to do with the car putting the radiator fan on more, on and off causing the revs to climb slightly? you can hear it when the car is warm if your at the front end.

This could be it as the fan was running but surely it should stay at a constant engine speed to cope? never had this kind of behaviour on a car before.

 

[Dan_DJT]

This could be it as the fan was running but surely it should stay at a constant engine speed to cope? never had this kind of behaviour on a car before.

Sounds like idle is increasing to cope with the fans demand, idle on these cars is really fragile, I blame the emissions regs for that

 

[Sequence]

Sounds like idle is increasing to cope with the fans demand, idle on these cars is really fragile, I blame the emissions regs for that

May be it then, i have been out again and realised it will happen only when ac is off, if ac is on then it idles fine. so increased engine speed while running ac is enough to run the alternator more and run the fans without the need for more.. ****** aggressive emission controls