1996 Ford Probe idles too high

1996 Ford Probe SE mileage: 62,000.There are two symptoms, possibly related. Both problems are intermittent, but occur approx. 70% of the time. 1.High idle at around 2200 RPM, only when fully warmed up, especially when stopping at a traffic light after highway driving.It will stay at 2200, and then gradually reduce to around 1500 RPM before returning to normal. This process usually takes thirty or more seconds, sometimes over a minute. 2.When in "high idle mode", the engine will cut out at full throttle.I noticed this one-day when the high idle made, me made and I tried to make a jackrabbit start when a light turned green!Through each gear (5 speed), it will drown out at full throttle, and I have noticed that it smokes (gray) when I hold the pedal down during this cutout time, and smells really fowl-- like a combo of a catalytic converter and raw gas.Any ideas?I have been putting this off for a few months now, but it is getting worse.I drive about 2500 miles per month and feel like I may be stranded soon!