My alero idles fast

You can try a drive cycle, see if it helps? There may be an idle relearn, if just idle issue? Usually it will relearn idle on its own by driving.
Drive Cycle Recommendations:

1. Most OBDII monitors will complete more readily using a "steady foot" driving style during cruise or acceleration modes. Operating the throttle in a "smooth" fashion will minimize the time required for monitor completion.
2. Fuel tank level should be between 1/2 and 3/4 fill with 3/4 fill being the most desirable.
3. The Evaporative Monitor can only operate during the first 30 minutes of engine operation. When executing the procedure for this monitor, stay in part throttle mode and drive in a smooth fashion to minimize "fuel slosh".

WARNING
STRICT OBSERVANCE OF POSTED SPEED LIMITS AND ATTENTION TO DRIVING CONDITIONS ARE MANDATORY WHEN PROCEEDING THROUGH THE FOLLOWING DRIVE CYCLES.
For best results, follow each of the following steps as accurately as possible:
OBDII Monitor
Exercised Drive Cycle Procedure
Purpose of
Drive Cycle Procedure Drive Cycle
Preparation 1. Install scan tool. Turn key on with the engine off. Cycle key off, then on. Select appropriate Vehicle & Engine qualifier. Clear all DTC's/ Perform a PCM Reset. Bypasses engine soak timer. Resets OBDII Monitor status. 2. Begin to monitor the following PIDs: ECT, EVAPDC, FLI (if available) and TP MODE.
Start vehicle WITHOUT returning to Key Off. 3. Idle vehicle for 15 seconds. Drive at 64 Km/h (40 MPH) until ECT is at least 76.7°C (170° F). Prep for Monitor Entry 4. Is IAT within 4.4 to 37.8°C (40 to 100° F)? If Not, complete the following steps but, note that step 14 will be required to "bypass " the Evap monitor and clear the P1000. Engine warm-up and provide IAT input to the PCM. HEGO 5. Cruise at 64 Km/h (40 MPH) for up to 4 minutes. Executes the HEGO monitor. EVAP 6. Cruise at 72 to 104 Km/h (45 to 65 MPH) for 10 minutes (avoid sharp turns and hills) Note, to initiate the monitor: TP MODE should =PT, EVAPDC must be >75%, and FLI must be between 15 and 85% Executes the EVAP Monitor (If IAT is within 4.4 to 37.8° (40 to 100°F)) Catalyst 7. Drive in stop and go traffic conditions. Include five different constant cruise speeds, ranging from 40 to 72 Km/h (25 to 45 MPH) over a 10 minute period. Executes the Catalyst Monitor. EGR 8. From a stop, accelerate to 72 Km/h (45 MPH) at 1/2 to 3/4 throttle. Repeat 3 times. Executes the EGR Monitor. SEC AIR/CCM (Engine) 9. Bring the vehicle to a stop. Idle with transmission in drive (neutral for M/T) for 2 minutes. Executes the ISC portion of the CCM. CCM (Trans) 10. For M/T, accelerate from 0 to 80 Km/h (o to 50 MPH), continue to step 11. For A/T, from a stop and in overdrive, moderately accelerate to 80 Km/h (50 MPH) and cruise for at least 15 seconds. Stop vehicle and repeat without overdrive to 64 Km/h (40 MPH) cruising for at least 30 seconds. While at 64 Km/h (40 MPH) , activate overdrive and accelerate to 80 Km/h (50 MPH) and cruise for at least 15 seconds. Stop for at least 20 seconds and repeat step 10 five times. Executes the transmission portion of the CCM. Misfire & Fuel Monitors 11. From a stop, accelerate to 104 Km/h (65 MPH). Decelerate at closed throttle until 64 Km/h (40 MPH) (no brakes). Repeat this 3 times. Allows learning for the misfire monitor. Readiness Check 12. Access the ON-Board System Readiness (OBDII monitor status) function on the scan tool. Determine whether all non-continuous monitors have completed. If not, go to step 13. Determines if any monitor has not completed. Pending Code Check and Evap Monitor "Bypass" Check 13. With the scan tool, check for pending codes. Conduct normal repair procedures for any pending code concern. Otherwise, rerun any incomplete monitor.
Note: if the EVAP monitor is not complete AND IAT was out of the 4.4 to 37.8° C (40 to 100° F) temperature range in step #4, or the altitude is over 2438 m. (8000 ft.), the Evap "bypass" procedure must be followed.Proceed to step 14. Determines if a pending code is preventing the clearing of P1000. Evap Monitor "Bypass" 14. Park vehicle for a minimum of 8 hours. Repeat steps 2 through 12. DO NOT REPEAT STEP 1. Allow the "bypass" counter to increment to two.
© Ford Motor Company

Take extra caution while performing dirve cycles on public roadways. Drive cycles can be difficult to follow under normal driving conditions. Begin by: - Start the engine. Idle the engine in drive for two and a half minutes with the A/C and rear defroster on. - Turn the A/C and rear defrost off, and accelerate to 55 mph at half throttle. - Hold at a steady speed of 55 mph for three minutes. - Decelerate (coast down) to 20 mph without braking or depressing the clutch. - Accelerate back to 55 to 60 mph at ¾ throttle. - Hold at a steady speed of 55 to 60 mph for five minutes. - Decelerate (coast down) to a stop without braking. If all other emissions systems are functioning properly, completing the drive cycle above will set the "readiness flags" required to pass the smog check. It will not hurt to perform the drive cycle 2 or 3 times before the smog test.

My first guess would be a sticky throttle plate or a major vac leak.
But there should be trouble codes if it won't idle at a normal speed.

To me it sounds like the (fuel pressure valve) located on the end of the fuel rail, by the throttle body, also check vacuum line.

throttle position sensor

You are probably having an issue with your IACV idle air control valve located on your throttle body. When the IACV goes out you lose control of your idle. The car may not idle at all or you could find yourself driving down the road at 50 MPH without touching the gas pedal.

TPS switch on throttle body

Check the base plate gasket under the throttle body, some time the gasket start to leak, and will cause a high idle, if possible with engine running get some water and pore it at the base of the throttle bode, you will hear a suction sound, that's the gasket, replace it.

the idle air control valve is stuck,or there is a vacuum leak.check the vacuum lines,the throttle cable is not sticking and the idle control valve which is on the side of the throttle body and the throttle position sensor.check all the plugs on these for a good connection.

I'm not sure if you've found the answer to your question yet...but i'm having a simlar problem with my car it could possibly be the Throttle Position Sensor. Simple explanation from what I understand it tells the engine how much your pushing on the gas pedal and if this peice is off it can send misreading to the engine causing high idle. I replaced it in my car and it works fine now. Park was $30~ at Auto Zone.