Bill, thanks. that's great information.

Yesterday (after the car had sat overnight), it fired right up. Today, it cranks strangely and almost fires, but never actually starts up.

Following your advice, I can confirm power to the pump, fuel at the rail, and 12v across #2 fuse. Whatever is going on, it seems to shift around quite a bit... The electrical gremlins have returned...

Unfortunately, I can't locate a relay #106.

Left-to-right, there's a twin hella relay, fuel pump (103), and a twin lighting control relay. I believe that these are marked as 102, 104, 103, 105, and 108. Under the dash, there are several relays, but none of these are marked as "106"

Between those relays and the fuse panel there are three four-prong "J" relays.

Above the radiator there's a fan control relay, and an unidentified grey relay with four bullet connectors. I assume this the injector safety relay, you mentioned. I can confirm that it "clicks" when I switch the ignition.

I can also confirm good solid ground between the motor and the body.

I also unscrewed and lifted the fuse/relay panel and checked the connections underneath. No loose connections or damaged wiring. There were two clipped wires that I traced back to an old car-phone setup, but these were dead-ends and have been removed.

If you recall, this is the car with the self-opening sunroof and the #3 fuse that kept draining the battery last summer.

I still haven't traced the sunroof issue, but removing the #3 fuse stopped the battery drain.