Where is the PCM located?

High idle but no other issues is commonly a vacuum leak or IAC problem not a PCM failure. I would start there myself as the PCM would normally be showing a code 35 and not just a high idle. Don't forget to check the power brake vacuum line as well as a bad vacuum booster could also cause a leak. The attached shows the vacuum lines in question. The easy way to tell if it's a vacuum leak is to start with a cold engine and a can of carb cleaner. Start the engine and spray the cleaner along the lines and around the intake manifold gasket area. For the brake booster, disconnect the line and plug it.
If you are sure it's a bad pcm then it is under the left side of the dash in a carrier between the steering column and the kick panel.

If the IAC didn't adjust I would start with the leak testing. They may have closed down because the idle was already too fast and they couldn't make it lower. If you don't find any leaks then we will do some testing on the electronics to see if there is a wiring issue, but vacuum leaks are common as the rubber parts age and decompose. Washing machines are fun to work on.

Okay, that means the IAC isn't adjusting itself and is stuck wide open. The IAC in that vehicle uses 2 coils that move the stepper motor to move the pintle to block the passage. The IAC is supposed to reset to full closed when you shut off the car then it opens back up when the engine starts. They make a special service tool for it or if you have an OBD I scan tool that can adjust it you could easily test it. To test it without a scan tool you can use a test light to probe into the back of the connector with needles. Then you could watch to see if the power is there to pulse the IAC, Then you would go to the PCM and check the connections there. That would show you if it's the wiring or the PCM output. There are a few videos out there that show how to back probe the connector. That lets you test it with it installed.
The light would get connected to one pair then to the other pair. So the two light green wires, then the two blue wires. It should blink as the IAC adjusts.

We will be here when you need us.

There could be a bad gasket and the rebuild kit does contain them, but that passage should go down to the IAC. The IAC should extend out and block a hole inside the throttle body. When you block that port you are acting as the IAC motor.
You have power on both sets of wires? That means it shouldn't be the PCM, it's something with the IAC or the throttle body. Perhaps pull the IAC off and check in there to be sure the seat is clear and nothing is there to hold it open.

The rebuild kit is a Standard Motor Products #1695 rebuild kit. If it's a bad gasket or internal issue that kit should repair it.

Hi,

I noticed no one has contacted you for a couple of days. Have you been able to make any progress?

As far as the PCM, it is located to the left of the steering column under the dash. The mount that holds it in place also holds the ABS module. I attached a pic below.

Let me know if that helps. Also, pic 2 provides the original part number. Note there are two. One is for an automatic transmission and the other is for a manual transmission. I'm not sure which you have.

Let me know if you have other questions.

Take care,

Joe

See pics below.