It seems not many people are aware of this but should be, whilst you can diagnose issues via the flashing CEL there is also the option to connect an OBD2 scanner to an OBD1 car so you can view live data of most sensors with graphs, and pull codes but note they will appear with OBD2 numbers, this also shows ATX codes. You can view almost everything live, TPS voltages, o2 sensors, IAT temp and voltage, MAF voltage, RPM, EGR etc.

To do this you need an ELM327 OBD2 scanner, a Mazda 16pin to 17pin OBD2 adaptor cable or three wires.

If you want to do it with three wires, here is the pinout, note that the OBD2 pinout is from a harness connector so needs to be reversed to hook up to the OBD2 itself.
How to connect FORScan to pre-CAN Mazda - FORScan forum




For Mazda OBD1 17 Pins to OBDII 16 Pins Cable Adapter
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