94 Camry would die and then start up after 20-30 minutes and many tries. Now won't start at all. Here is what we have done and tested. Getting a code 12.
1. Changed dist. cap, rotor.
2. Test coil both primary and secondary have correct resistance reading.
3. Test other coils in distirbutor and they have correct readings.
4. Also tried a swap out of main coil, did nothing and new coil had same readings.
5. Swapped out Igniter nothing different.
6. Checked voltage at dist primary OK
7. Checked voltage at igniter, OK
8. Even watched ohm reading on distributor as we turned shaft and when lobe passes small coils the ohms drop.
9. CHecked air gap on dist coils and lobes, OK
10. We have no spark.
11. Fuel pressure OK
12. Our last resort seems to be ECM.
13. Could it still be distributor?

Thanks...

. Like you, I suspect there may be a problem with the ECM. Try installing a known-good ECM.
. Check for an open between the crankshaft position sensor and the ECM.

It could be wiring going to the dist. One is for crank signal, and the other is for cam signal. Check for any broken or opens in the dist area. These connectors/wires get very fragile in the older cars once disturbed.
By the way, I've said this many times in my previous answers on this forum that only use a Toyota coil if you are replacing it. 9 out of ten times it is the coil even though your readings are spot on. Auto Zone or aftermarket coils just don't seem to cut it in your camry.
Be sure your dist rotor is pointing #1 at TDC. This will tell if timing betl hasn't slipped.