91 Seville - Engine kills when Shift Lever is Moved

4.9, 120k mi, console shift, solid car, good runner until recently. When shift lever is moved from P to R or P to D or D to N or whatever, the engine might kill, it’s random, no pattern noticed. Waiting several hours or overnight might allow restart. Moving key position from Lock to Run to Start yields nothing, starter dead quiet, no solenoid clicks, instrument panel lights do not function. Accessories not tied to ignition switch (seats, locks, mirrors, lights, etc) work OK.

On restart, engine, trans and accessories all function well. One never knows when moving shifter will kill engine. It could happen at start up with cold engine or after running for some time.

Swapped neutral start switch, no change. Opened console to check for linkage hanging up on wiring, all looks clear.

My reference manual is not very detailed. There is a molded plastic case to the right of the shifter - is this a sensor housing? Any tips on checking ignition switch? Manual describes changing it but not checking function.

Need to get running so my son has wheels for work during semester break. I am currently unemployed an have limited resources. Thanks to all for help.