I have a 96 Explorer Eddy Bauer w/about 80K miles (hard to believe I know, but that is accurate). It stalls in hot weather-above about 80-when I start it up and continues to stall at lights, etc. The "check engine" light has come on, but it seems okay in cooler temps-around 70 or so. The idle drops in the higher temps, which is probably the cause, but what is causing that to happen?

I'm guessing it is the O2 sensor, idle control or as I saw in one post here-the fuel pressure regulator. Is there a TSB on this? This problem has been happening since it was new, but the previous owner (my dad) never took it back to Ford to get it fixed.
Thanks.