My 1993 Camry was stalling at stop-lights and such, but intermittently - and never at the shop of course. The pattern seemed to have nothing to do with the outside temp, humidity, rainfall, or whether the car was warmed up or cold - or anything. When it stalled sometimes it would start right away and sometimes it took up to a minute before it would restart. Usually I would be able to smell gas when it stalled (if the car's vent was set to bring in outside air and the wind was blowing in the right direction).
I followed the advice offered on this newsgroup over the years (via google) - in a step-by-step scientific fashion: I tried dry gas, replaced filters, then put myself at the mercy of the local Toyota dealer who cheerfully charged me for a major tune-up, a new GRC valve, and a new distributor. Still, no improvement. Instead the problem slowly got worse (more frequent). Typically I could not drive five miles without it stalling at least once at a stop, although now and then it would go a day or two without stalling at all.
Back at the dealer again they recommended a very expensive carburetor overhaul. I asked them to check the engine coolant temperature sensor (ECTS) first - another item suggested on this newsgroup. But the service manager looked at me like I was a space alien that just landed in front of his desk. He seemed - shall we say - skeptical about the idea. I had the feeling he was trying not to laugh. So, I took my car down to the local library (stalled twice) and looked up info on the ECTS in the Mitchell's guide my library - thankfully - owns. I removed the sensor (which is really really easy - it has brown and light green leads - just remove the connector and unscrew it), hooked up a multimeter to the leads, and dunked it and a thermometer in hot and cold water of various temperatures. I watched the multimeter read out the ohms and checked it against the temp/ohm chart in the Mitchell's guide. The result - it was in perfect condition. Next I decided to check the air temperature sensor, which is basically identical. But I had to do some errands so I put the ECTS back in and drove off. And drove and drove and drove and it did not stall. Over the next few weeks I put a hundred miles of stop and go driving in and it never once stalled. My theory: the electrical contact to the ECTS was flakey - and so just jiggling the wires to the ECTS would have been enough to fix my problem. So, about $500 poorer - but richer in knowledge and wisdom - I fixed my own problem by essentially jiggling two wires.
The moral of the story: wiggle the wires first.
=r.e.