high idle

My 1989 S-15 2.5 liter pickup idles too high.On some occasions it will high idle, even when warm, then stumble when shifted into gear and then quit. It seems to smell gassy after it quits, and acts as if it may be flooded. What could this?
Thanks

check the idle air valve, or the throttle position sensor.

My 1989 S-15 2.5 liter pickup idles too high.On some occasions it will high idle, even when warm, then stumble when shifted into gear and then quit. It seems to smell gassy after it quits, and acts as if it may be flooded. What could this?
Thanks
If the throttle body sounds like a huge pump sucking in air it is your IAC Idle Air Control expense part but the problem most likely if you have that being an 89 or it is a vacuum leak could be warn out hoses start with that first, cheaper!!