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Jay, Chevy Mechanic
Category: Chevy
Satisfied Customers: 596
Experience:  Several yrs experience, GM Trained,
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2005 Chevy Aveo: rpm when on idle, while the car is..10 seconds..leaks

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I have a 2005 Chevy Aveo with 48K miles. The car has developed an increase of rpm when on idle, while the car is in motion, once you stop completly, it will take about anywhere from 4 to 10 seconds for the rpm to go down to the 800 rpm that normally it will be at idle. Check for leaks or broXXXXX XXXXXnes, all appear to be fine. The sudden increase of rpm can fluctuate between 1200 and 2000 rpm. The car has manual transmission. Took to the dealer, they can't find any codes and no answer to the problem. I suspect defective throtle positioning sensor.
I notice that if the car is stationary and roll down like on an incline, the rpm will go up and then when I stop, it will gradually go down after 10 to 15 seconds.

HelloCustomer the problem is most likely the throttle body itself, but if you can perhaps replacing the sensor will help. Please reply if you have questions, thanks.

Customer: replied 7 years ago.
What can be wrong with the throttle body, or how can I confirm that in fact that is the problem? The problem comes and goes and is not constant.
Does your vehicle have the throttle actuator control, meaning that the throttle is controlled by electronics rather than a cable.
Customer: replied 7 years ago.
Is cable control. I know that in the throttle body it has an idle control valve, thats the only electronic piece I have found on that location.

HelloCustomer I'll go back on the throttle body. Without codes it makes it tough to know for sure and if you correctly checked everthing that you said you did then, the most likely piece is the idle air control valve causing the problem. The TPS if it were faulty would definitely set a code. Here is some instructions, thanks:


Idle Air Control Valve Replacement

Removal Procedure

    Caution: Refer to Battery Disconnect Caution in the Preface section.

    Object Number:(NNN) NNN-NNNN Size: SH

  1. Disconnect the negative battery cable.
  2. Disconnect the idle air control (IAC) valve connector.
  3. Remove the IAC valve retaining bolts.


    Do Not push or pull on the IAC valve pintle on IAC valves that have been in service. The force required to move the pintle may damage the threads on the worm drive.
    Do Not soak the IAC valve in any liquid cleaner or solvent, as damage may result.


  4. Remove the IAC valve.
  5. Clean the IAC valve O-ring seal area, the pintle valve seat, and the air passage with a suitable fuel system cleaner. Do not use methyl ethyl ketone.

Installation Procedure

    Object Number:(NNN) NNN-NNNN Size: SH

    Important: If installing a new IAC valve, be sure to replace it with an identical part. The IAC valve pintle shape and diameter are designed for the specific application. Measure the distance between the tip of the IAC valve pintle and the mounting flange. If the distance is greater than 28 mm (1.1 in), use finger pressure to slowly retract the pintle.

    The force required to retract the pintle will not damage the IAC valve. The purpose of the 28 mm (1.1 in) setting is to prevent the IAC pintle from bottoming out on the pintle seat. This 28 mm (1.1 in) setting is also an adequate setting for controlled idle on a restart.



  1. Lubricate a new O-ring with engine oil. Install the new O-ring onto the valve.
  2. Install the IAC valve into the throttle body.


    Object Number:(NNN) NNN-NNNN Size: SH

  3. Install the IAC valve retaining bolts.

    Tighten the idle air control valve retaining bolts to 3 N·m (27 lb in).

  4. Connect the IAC valve connector.
  5. Connect the negative battery cable.
  6. Perform the idle learn procedure. Refer to Idle Learn.
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