I have a meticulously cared for 2003 Camry. When I got it a year ago it stalled at startup about 10% of the time, and it has increased to almost 50%. The engine light is on and off, but seems to have no bearing, nor does air or engine temperature. If I keep my foot on the gas even when stopped, I can drive it. Sometimes it warms up to idle, sometimes not. It stalls usually at start and always when going slow or stopping. Sometimes it succeeds in idling, sometimes it fails, but never something in between. Either it idles right at 1000rpm, or at 0.
Mechanic ran it through the computer, drove it around, tried it a bunch of times and found nothing.