I have had this problem for the entire 4 years that I've had my 2003 Ford Escape. Fall and Winter the car runs great; no problems whatsoever. As soon as the weather gets warm, it starts and runs just fine in the night and morning or if it has been parked long enough to cool down, but if I make a short stop somewhere and it has cooled off just a little or if the weather is really hot, the car will start just fine, but it will not run. The idle "speed" seems to be set at zero! Whenever I take my foot off the gas it dies instantaneously and I am stranded until it cools off. Last year when the weather temperature was over 100, it would not run until the sun went down! Every year I have taken it to the Ford dealer and they have claimed to have been stumped, as it does not throw codes, and they have done something expensive every year. Changing manifold gaskets, reprogramming car computer, etc.
Well you can guess, today it happened again and the weather is only in the 70s. I made a long shopping trip of about an hour and it started up OK because it had time to cool down. Then I made a short stop of about 5 minutes to get some lunch and no go.
I waited and waited but the engine temp gauge wasn't going down much and the idle speed was absolute zero. I could very gently let off the accelerator and as long as I didn't let it go below 1000 it would run, so I finally decided to try shifting it with left foot on the brake and my right foot keeping the tach at 1000, and I managed to get out of the parking lot and drive home in a very roundabout way to avoid traffic. Normally it would have been 7 miles home, but I went down all the country lanes at in second gear and slow speed in about a 20 mile loop and restarted in neutral while moving whenever it died. When I got about 10 miles I was going along at 2000 rpm and suddenly it felt like it shifted gears on its own but the rpms did not change. The car suddenly felt way more powerful and sure enough something in the control system had shifted and the idle speed when I took my foot off the gas was back to its normal 1200-1500 rpm. It ran perfectly from that point on.
From my searching this evening I have found that the problem almost certainly must be in either the idle air control valve (IAC) or the mass air flow sensor (MAF) (or both). I am tired of getting stranded so I am going to have those parts and their gaskets replaced and I am willing to bet it's going to work and I am not a gambler.