High idle rpm

[Tidyflow]

Hello there
Im all new to this, recently purchased 2008 polo gti.
Had it for 3 weeks now so far its ok...a frw minor things here and there.
Notice something strange when went out driving last night
My standing still idel rpm was at 900rpm not the usual 700rpm...when I take off and drive for a longer stretch then stop at the lights it was back to the usual 700rpm...so then I took off again this time it was a quick start and stop half way up yhe street then it was back to 900rpm again...no miss firing nothing..engine running smooth.
And today I was driving around in the afternoon and it was fine and it didnt idle at 900rpm at all just a steady 700rpm.
Should I be worried?

[sambb]

As long as its steady I'd have thought you'd be ok. At night if you have the stereo going and headlights on it can load the engine which will affect the idle. Then during the day you may have had the AC on switching in and out. The only real way to tell is have everything turned off and the car warm and see then if you get a variation. My idle rpm was always consistent but it'd get big dips and hiccups. This turned out to be the SAI system which I'm pretty sure may still gets signalled to run even if the car isn't at cold start. Since I did the delete It hasn't happened once.

[Tidyflow]

As long as its steady I'd have thought you'd be ok. At night if you have the stereo going and headlights on it can load the engine which will affect the idle. Then during the day you may have had the AC on switching in and out. The only real way to tell is have everything turned off and the car warm and see then if you get a variation. My idle rpm was always consistent but it'd get big dips and hiccups. This turned out to be the SAI system which I'm pretty sure may still gets signalled to run even if the car isn't at cold start. Since I did the delete It hasn't happened once.

Thankyou so much for the info much appreciated.
Been driving around all day today in the afternoon and it seems to be in the usual idle 700rpm.
I will keep an eye on it and do what you said.
Cheers