1998 Isuzu Rodeo Question IDLE

Since its idling high first thing I would check would be for vaccum leaks, you can do this buy using a piece of fuel line and listening one end while probing with the other, when you find a leak itll make a sucking sound.

The easier way would be with a smoke test or you can use a can of carb cleaner and spray all gaskets, hoses. When you find the leak, the idle will change.