Standard clutch. high idle after warm up. restart engine, high idle ceases only to begin again after accelerating. already replaced idle controller though no engine lights were detected. Also performed computer analysis. No read outs. Could it be intake gasket? too much air flow? High idle also happens when I restart engine, place car in neutral, sit for about 3-5 minutes. Engine revs up again. Thanks.

SOURCE: HIGH IDLE, 1500rpm

No, its the intake manifold gasket.  This is a very common problem with the SL/SL1 engine.  There are only three bolts around the #1 cylinder and no bridge in the block between #1 and #2 cylinders.  The flexible factory gasket tends to pull out in this area.
A confirmation of this is to spray some carburetor cleaner, fuel injector cleaner or even WD40 on the gasket around the #1 cylinder and if it affects the idle in any way, its because its leaking.
Felpro makes a good replacement gasket.

SOURCE: high idle/low idle pattern

This issue is caused by the egr valve being stuck open, more than likely. Just remove it and clean the plunger on it. Also clean out the two ports that are in the intake. Check out saturnfans.com for more information. I hope this helps.

SOURCE: 2000 SL-1 fast idle problem during cold weather only

You need to check and/or replace the thermostat and/or the temp. sensor. Take a meat thermometer and stick it in the overflow tank. The temp gauge on the dash should register above the 1/4 mark after at least 15 minutes of driving. If so, the meat thermometer should read above 180 degrees. If the meat thermometer reads 180 but the gauge isn't above 1/4, then you need to replace the sensor. If the meat thermometer doesn't read 180 or higher, then you need to replace the thermostat. The thermostat in these cars, though it doesn't fail on its own, has an unnecessary rubber gasket that fails, and allows coolant to leak past even when shut, causing the engine to not warm up thoroughly. IF the engine doesn't warm up, the idle won't come down--speaking from personal experience. I had to replace both items on my car. Now it idles fine, and after a bit of driving the gauge registers between 1/4 and 1/2, but always above 1/4. DO NOT tamper with idle adjustments unless you have exhausted all other possibilities. They are factory set, critical, and almost never need readjusting. Good luck.

Bruce Bracey

• 1000 Answers
• Posted on Feb 09, 2009

SOURCE: idles high

Zab, First things first, check for any vacuum leaks, hoses that are disconnected, cracked or just plain worn out. Also check for vacuum leaks around the throttle body.
It really sounds like you have an EGR valve that is stuck open ever so slightly. The MAP sensor is a result of a low manifold vacuum. The IAC (idle air control) motor is trying to compesate and keep the engine running resulting in the high idle speed. I would remove the EGR valve and clean it gently with a brush and pick to remove any carbon build up.
Let me know, regards.

SOURCE: 2001 Saturn Sl1 1.9 Code P0404

Spray carb cleaner around #1 intake runner,known to blow gasket there,Replace leaner egr valve.