1998 Ford Mustang Intermittent high idle, idle drop, stumbl

My car has recently developed an intermittent problem involving: high idle (2k-2500 rpms), idle that drops too quickly when I let my foot off the gas and a stumble or misfire in all rpm ranges. It doesn't matter if the engine is cold or at operating temp. It doesn't matter what the weather is like. Sometimes it will be fine when I start it up and drive alittle. Other times it is acting up as soon as I start it. Today, it started and immediately stalled and then all I smelled was gas (flooded, I assume). No symptom shows up without the other. I have noticed that it generally only shows up when I've come to a stop or when I'm about to come to a stop. I'll know it's about to happen when the idle rpm surges up to 2k and holds there. When I accelerate, it stumbles or misfires and when I let off the gas to shift the rpms drop very quickly.