High Idle Before Warmed Up

[Binari]

I really enjoy reading the posts on LOC. This site has saved me over a $1K so far, and maybe you guys and gals can help me figure out an annoying problem.

Anyway, my LS idles at 1200 after starting, and will not settle into 600 RPM until fully warmed, and sometimes I have to shift to N or P at a stop light before the idle will fall to the correct level. When it idles at 600 RPM at full stop she rides and shifts just fine. When she is warming up or idling high, she coasts with a high RPM and does not decelerate.

For example, if I take my foot off the gas approaching a freeway exit, she will maintain the RPMs and speed as if in cruise control. I have to apply the brakes to slow down and the RPMS will come down, but if I take my foot off the brakes before the engine down shifts, like when the engine is at 1400 RPM she will coast at that RPM and that same speed until the transmission down shifts. On flat ground it will maintain 40mph with foot off the gas with no deceleration.

Most times after coming to a stop the engine will idle high unless I put it in park or Neutral and then for some reason the RPM falls to 600 and then she runs properly (I.E. she decelerates without the cruise control like coasting).

I started thinking it may have something to do with one of the air control values, or a vacumn tube to the transmission.

To complicate things, I bought the LS a month ago with 99.4K miles and the first thing I did was the Timing belt/Water Pump, Spark Plugs/Wires/Rotor/Cap replacement. So I have no history on how the vehicle drove before i did the 90K maintenance. I may have goofed something up but she gets 23MPG on highway, and seems to run smooth and well other than the issue I noted above.

Any ideas are appreciated.

Thanks,

Ed

[jgr7]

Check out these threads.

http://us.lexusownersclub.com/forums/index...showtopic=30723

http://us.lexusownersclub.com/forums/index...showtopic=11748

[Binari]

Thanks for that. I checked out those threads and the fix seemed to be for low idle and hard starting. I don't have a problem starting and no low idle problem. I may clean the IACV anyway because it probably needs it. I was hoping it was something that simple but we will see when I get around to doing the task.

Cheers,

Ed