Idle at 1700 rpms sometimes

[DeNoZZo]

I was driving my car the other day and when I came to a stop and put the car in neutral, the idle stayed around 1500-1700 rpms. It came back down to the normal 750 after a while, but what would cause it to rise like that? One of my friends things it's the coolant temp sensor freaking out thinking the car is cold and raising the idle to heat it up.

 

[NycDSM11]

my car does the same thing but only when its in open loop(not warmed up) does i t only happen when the car is not in operating temp?

 

[95blackGsTurbo]

It can be a combination of many things, ECT sensor, ISC, FIAV, could just be the cold air causing the idle to be raised temporarily. I would search on proper methods of testing the sensors and check them out. You could even have a boost leak sucking in minor amounts of unmetered cold air, that will raise the idle until the IAC can compensate for it.

 

[awd_tsi91]

def a coolant sensor possibility! i had an issue like that and then it got worse to where i had to replace my ecu