The diagnostic sign that it is indeed the crankshaft sensor is that revs drop to zero despite the engine still turning. The cable goes from the bell housing at the transmission to the ignition module at the left fender.
Another option could be faulty O2 sensor. It starts to operate with the coolant above a threshold temperature. If it provides false information, the mixture adjustment is screwed up. Or faulty coolant temperature sensor.
Or, the first thing to always check: Rotor, distributor and ignition wires.

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1992 300TE 160 kmiles