Extremely high idle question

[stinknugget]

I am wondering why my 2000 SL with 113K miles idles so high. After initial warm-up at around 1500-2000 rpm it jumps way up to 3000-3500 once I get started driving. I also notice that even at the high idle and driving at high speeds, my temperature gauge barely gets to the halfway mark, when it used to go to just over the mark every time. Any suggestions?

 

[William Hughes]

I am wondering why my 2000 SL with 113K miles idles so high. After initial warm-up at around 1500-2000 rpm it jumps way up to 3000-3500 once I get started driving. I also notice that even at the high idle and driving at high speeds, my temperature gauge barely gets to the halfway mark, when it used to go to just over the mark every time. Any suggestions?

I just had a similar problem with my '95 SW2. Turned out to be a bad coolant temperature sensor - $8 at AutoZone.

 

[jdoe]

I had the same thing too and replaced the colant sensor. But it didn't help. Finally replaced the Automatic Idle Air Control Motor and all is well. Make sure you don't have any other suspects like a vacum leak too.
Larry