idle sensor?

[mikek]

2001 sc2 idles fast sometimes. I can shut it off and it rumbles to a stop,
starts fine and the idle is normal. It is very random...any ideas? I dont
get a service light either.

 

[jdoe]

Similar problem on my 96 SL2. Was told ECTS (coolant temp sensor) but I put
new one in and no help. I'm still fighting with it, but am leaning toward
the IAC solenoid.
Larry