How is idle controlled on 89 GT?

[barchetta]

I am looking at purchasing a 1989 Celica GT (in addition to the 76 I am attempting to restore, but that is a whole different discussion), but the car has a very high idle. The idle is stuck at 3000.

There doesn't appear to be any binding of the throttle linkage since it easily revs higher, and then back down to 3000. The engine was at normal operating temperatures. I blipped the throttle to see if the engine idle would drop back down, but it only went back to 3000.

My question: Is the idle for this car controlled by the ECU, or a mechanical means? I am looking to pick up the car cheap, and I was not looking to spend too much to make it a daily driver for one of my kids. Any help or opinions would be much appreciated.

[Deep]

If its a GT then its got an AFM, which meters air for the ECU. The IAC valve could also be at fault, along with a massive vacuum leak.

[Pineapple]

There maybe an idle screw on throttle body.
Like Deep say you may have a big leak or even cracked manifold. Usually bad ICV cause low, bouncy idle.