Engine Mechanical problem
1992 Plymouth Acclaim 4 cyl Front Wheel Drive Automatic 204000 miles

When it is hot and humid outside and I have driven for 30 mins or more, my car will sputter and die when I take my foot off accelerator (like coming up to a stop light). It starts right back up, but when put into drive, either immediately dies, or will barely move when given gas, sputter and then die again. Putting it down into 2nd helps a little, but will still die. After letting it sit off for 30 minutes or so, it runs fine. What might be causing this? Please help. I live in Kansas and it is summer - the heat and humidity aren't going anywhere anytime soon!