Thanks for using Just Answer, your vehicle's transmission modulator valve is located on the driver's side of the transmission.
As far as the rough idle, the most common cause is a stuck or defective IAC (Idle Air Control) valve mounted on the side of the upper intake.
The idle air control valve (IAC) control the engine idle speed and dashpot functions. The valve is located on the throttle body on. This valve allows air to bypass the throttle plate. The amount of air is determined by the Powertrain Control Module (PCM) and controlled by a duty cycle signal.
Due to the diode in the solenoid, place the ohmmeter positive lead on the VPWR pin and the negative lead on the ISC pin.
1. Unplug the connector at the IAC valve.
2. Remove the two screws retaining the IAC valve
3. Remove the detached IAC valve from the throttle body
4. Remove the gasket from the throttle body and discard.
The IAC is more than stuck shut due to excessive carbon build up, the IAC is relatively an inexpensive part and is in need of replacement. The IAC can be purchased at any local auto part store.
I was just re reading all the posts and I noticed that you said that you've cleaned the spark plugs.
I would recommend using the proper plugs, such as Motorcraft SP-450.
Also double check the spark plug Gap .044 (In thousandths of an inch).
And finally, inspect all vacuum lines making sure that there are no splits or cracks, or even disconnected. Try spraying carb spray around all vacuum line fittings as well as the intake manifold and monitor for any change in the idle. If idle increases when spraying then you've located the leak. Hope this helps you out.
More than likely the transmission that you have is an AOD. The modulator is on the driver's side of the transmission.
This is for the AOD
And this is the C6
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We need to find out if this transmission is an AOD, if it is then it does not require a vacuum modulator.
All vehicles are equipped with a Vehicle Certification Label, affixed to the LH (driver's) side door lock post.
Refer to the code in the space marked TR on the Vehicle Certification Label for proper transmission identification
For additional information such as: model, service ID level or build date, refer to the transmission ID tag which is attached to the transmission case.
The "T" only indicates that the transmission is an automatic.
Hi Customer ,
From the description of the pan, it seems like the transmission that is in your truck is an AOD and uses the Throttle valve, instead of a vacuum modulator.
Service Adjustment Procedure
Two methods of TV system adjustment are available.
1. TV cable adjustment with engine off.
2. TV control pressure check and adjustment procedure with engine on.
The Throttle Valve (TV) Control Cable System consists of a cable attaching stud on the throttle body throttle lever, the TV Control Cable Assembly, the External TV Control Lever on the transmission, and the Cable Mounting Brackets at the throttle body and transmission. As the throttle body lever is moved from idle to wide open throttle (WOT), the TV control cable pulls the transmission TV control lever from idle to WOT. Return of the cable and transmission lever towards idle is accomplished by the return spring on the transmission end of the cable assembly. This spring and the end of the cable assembly is protected by a flexible rubber boot. The transmission external TV control lever actuates the internal TV control mechanism which regulates the TV control pressure. The travel of this lever is controlled by stops internal to the transmission.
The TV control cable is set and locked to its proper length during initial assembly by pushing in the locking tab at the throttle body end of the cable assembly. When the tab is unlocked, the cable is released for adjustment. The take-up spring at this end of the cable automatically tensions the cable when released. With the slack taken up and the locking tab pushed in, the take-up spring plays no part in the operation of the system.
Here are some diagrams
And Click Here