1997 Cadillac Concours shuts off at light or turning corner

What is the condition of the maintenance? At over 100k miles, have your plugs and wires been changed? The way to differentiate original wires from replacements is cylinder #'s are on the original. Sometimes as the wires degrade, they can cause an intermittent stall, typically at low speed. It can only be described as thermal, or radio frequency interference affecting the ignition module. This is not the only potential cause, just a start. When it stalls, is it like the key has been turned off, by that I mean an immediate shutdown, not gradual. Does it start right back up, and seem normal. Does this occur typically after running at highway speeds, say coasting down an off ramp? As far as the idle increase, how severe is it? Could it be due to A/C compressor cycling?

At such a random occurrence, I would evaluate the ignition system, and if needed replace the plugs and wires. It is not necessarily going to set a fault code when this is happening, if anything a p1599 stall or near stall detected. The diagnostic information for this code is very general, and involves several checks and inspections. If it were fuel pressure related, I would speculate more of a graduated stall. Being sudden, you are either losing spark, or fuel injector pulse. It can potentially be involved to try and diagnose, the fact that it starts right up, adds difficulty as well. If the secondary is lacking maintenance at over 100k, we have to start somewhere.