Hi Bill. My vote is a flaky AMM, either internal or an intermittent connection. Peel back the boot and push in all pins. Next time you get a no-start, simply disconnect the AMM and if it now restarts (in limp home mode) then that's almost certain confirmation.

Also, next time you try to point a finger at the ECU, try to be a bit more refined in your diagnosis. By removing power at the battery you're resetting both the ECU and ignition controller (both data and capacitor charges) so you're actually pointing four fingers. First off, reset just the OBD section at the diagnostic connector. Reset just port 6 for the ignition side first then try a restart before a reset on port 2 for the fuel side. If neither makes a difference then selectively reset just the ignition controller or just the ECU using their fuses. Pulling power to clear things like the fuel trim program data should make no difference to starting, only returning to initial running conditions using default values.

I know you like thinking outside the box, sometimes to the point of seemingly grasping at straws, so with that kind of thinking I'll mention that after disconnecting the battery to remove power to all controllers and let capacitors discharge in the controllers, you are also letting the battery have a moment to recover a tiny bit of charge and when reconnecting there will also be a micro voltage surge that *in theory* could make a tiny difference in marginal connections -I'm thinking broken wire strands, weak connector contacts, weak grounds and marginal solder joints (thermal stress fractures) where signals might now be marginally okay, like from the AMM.
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now