It may not be running long enough to even set a code. May be safe to assume, as the OP has not commented on seeing a check engine light. The early ECMs were not all that smart in concluding what is wrong. They were barely fast enough to make the engine run. The next generation was tons better.
Hooking up a laptop can be done by purchasing an adapter cable and some try-before-you-buy software. You can verify sensors and commands. It would at least tell you what it is not, but you will still have to figure out what is broken. I would still use the techniques already given, as a stuck injector or a bad coil will not show up on the ECM. The ECMs are not that smart. You may see the injector pulsewidth slam wide open, but that could happen anyway as the ECM is just trying its best to keep the engine running. Don't let the ECM add confusion. Its still an engine with all the same mechanical parts of the old days. If it's not the fuel, its the spark, if it's not the spark, its the fuel.
