Idling Very High

What is year--make--model? Any applicable trouble codes? So your having trouble with idle? Remove throttle body, clean throttle bore and any small passages. Check and clean anything that has to do with idle air system.

006 Idle Speed Problems Idle Speed Wrong Do you have a professional type scan tool ? If not ,take it to a qualified repair shop .
007 Idle Speed Problems Scan Data for Idle

There are no provisions for adjusting the idle . The computer through the use of the IAC valve - idle air control controls the idle . There is a base idle set at the factory an should not be changed or messed with . What idle problem are you having ? low or high Could be IAC valve or air passages plugged . High idle the throttle plate could be gummed up an sticking ! If you were to change the base idle you cause check engine light problems .
How To Fix Car That Idles Poorly

Here's a picture of your egr valve,located by firewall.Here's your iac.

yes it has a idle air control motor try cleaning it or replace

These are all things that can affect your gas mileage and engine performance.

To check for vacuum leak, look for unhooked hoses on top of engine. If OK, use starter fluid and spray along intake manifold gaskets with engine running. If engine speeds up, there is a leaking gasket.

IAC deals with idle. Does the car idle smoothly? If not, remove IAC to see if it's dirty. I will paste instructions below for the IAC valve.

Throttle body dirty--what code is this? never heard of such a code, but you can clean the throttle body wioth carb cleaner. I will paste instructions below.

IAC valve info:

Operation The amount of air taken in during idling is regulated by the opening and closing of the servo valve located in the air passage that bypasses the throttle valve. The servo valve is opened or closed by the activation of the stepper motor (incorporated within the idle air control motor in the forward or reverse direction. Battery positive voltage is supplied, by way of the MFI relay, to the coil of the stepper motor. The engine control module switches ON the power transistors (located within the engine control module) in sequential order, and, when current flows to the stepper motor coil, the stepper motor is activated in the forward or reverse direction.

Removal & Installation

1. Disconnect the negative battery cable.
2. Detach the electrical connector at the sensor.
3. Remove the sensor from the throttle body.
   

To install:

1. Install the sensor in the opening in the throttle body and tighten the sensor.
2. Attach the electrical connector to the sensor.
3. Connect the negative battery cable.

Testing
Checking Coil Resistance

1. Disconnect the idle air control motor connector and connect the jumper (test harness).
2. Measure the resistance between terminal (2) of the connector at the idle air control motor side and terminal (1) or terminal (3). Standard value: 28-33 ohms at 68°F
3. Measure the resistance between terminal (5) of the connector at the idle air control motor side and terminal (6) or terminal (4). Standard value: 28-33 ohms at 68°F
4. If not within specifications, replace the IAC Valve.
5. If within specifications, check connectors and wiring between the sensor and ECM/PCM.
   

Checking Operation Sound

1. Check that the operating sound of the stepper motor can be heard over the idle air control motor when the ignition switch is turned to the ON position (without starting the engine).
2. If no operating sound can be heard, check the stepper motor drive circuit. (If the circuit is good, a defective stepper motor or engine control module is suspected.)

IAC picture--mounted on top side of engine.

Throttle body--loosten clamp to right of throttle body and pull hose off. Use electric parts cleaner or carb cleaner--spray on dirt with engine running. don't touch any sensors inside throttle body--sensors are delicate.

it's not old carbureted chevy, it's not idling high because there's too much tension on the gas pedal cable.

look at replacing/cleaning: idle control valve, maf(mass air flow sensor) vacuum leaks: intake manifold or air intake system.

Idle Air Control (IAC) Motor OPERATION The IAC motor is mounted to the throttle body and is operated by the engine controller. The throttle body has an air control passage that provides air for the engine at idle (when the throttle plate is closed). The IAC motor pintle protrudes into the air control passage and regulates air flow through it. Based on various sensor inputs, the engine controller adjusts engine idle speed by moving the IAC motor pintle in and out of the air control passage. The IAC motor is positioned when the ignition key is turned to the ON position.


OPERATION Found on V6, V8 and V10 engines, the intake manifold air temperature sensor is a variable, thermister type which reacts to temperature changes. In cold air, its resistance is high. As temperatures increase, its resistance decreases.






Fig. 2: Location of the intake manifold air temperature sensor — V8 engines


The sensor element itself extends into the intake manifold air stream to provide input voltage to the engine controller. This signal is used along with signals from other sensors by the engine controller to determine the fuel injector pulse width.

it's on the throttle body. Here's a Quest with same 3.0L engine. These often need cleaning with carb or throttle body cleaner

Idle Air Control (IAC) Valve When the engine (6007) is running but not at idle, the throttle valve controls the amount of air admitted into the engine. The powertrain control module (PCM) (12A650) increases the fuel injection output in proportion to the increased airflow to achieve the appropriate air/fuel ratio. During idle, the throttle valve is almost fully closed. It is therefore necessary for the idle air control system to supply air for combustion during idle. The idle air control (IAC) valve allows a metered amount of air to enter the intake manifold (9424). The camshaft position (CMP) sensor detects engine speed and sends a signal to the PCM. The PCM sends a duty cycle (On/Off) signal to the IAC valve which allows additional air to enter the intake manifold. Air is added by the IAC valve to maintain the set lowest idle speed at which the engine can operate. The idle speed adjusting screw allows adjustment of the airflow into the intake manifold.


Fast Idle Control (FIC) Solenoid The fast idle control (FIC) solenoid helps maintain a constant idle speed while the air conditioning is operating. When the air conditioning is turned on, the front climate control panel sends out two signals. One signal is sent to the powertrain control module (PCM) (12A650) to engage the A/C compressor (19703). The second signal is a ground signal sent to the FIC solenoid relay, to engage the FIC solenoid. The FIC solenoid supplies additional air to adjust the increased engine load.

Intake manifold gasket. Leaking where intake meets head.