Car is a 91 740T wagon M46 with 270k miles on it. Silver like my sedan was!

Bought it last fall and put a lot of work into it when I bought it. Car was used little the last few years before and it was stored outside. Normal work was done to the car including oil and filter, fuel filter, plugs, rotor, cap, and wires. Some brake and exhaust work and slave cylinder which failed. I just had the timing belt, front seals and water pump done. Car was recently in an accident with air bag deployment and repaired by my Indy. Car has always been a little moody and would have good days and days when it ran a little "off".

Drove home one day and started to sputter and cough. Got it home and barely in the driveway (3 km to work). Codes showed an RPM sensor so I put a new one in. Still no start. Swapped the two black relays, no luck.
Finally had a hunch and put some fuel in it. Started up and ran! Drove out and filled up the tank. Fuel gauge doesn't move. It stays at about 3/4. Thought yeah I solved it. Actually runs smooth so I think the RPM sensor helped. Tach seems a little too smooth to rise but maybe it is just finally happy. Next time I want to go somewhere it doesn't start. FPR is dry. I can hear the main fuel pump run. White fuel pump relay is from 05 and looks new inside. I checked and do see spark. Looks small and weak but there is spark. Not sure what it is supposed to look like. I try the diagnostic test in pin 2 with the ignition on. All I get is the idle valve clicking the first few runs through the sequence and then the rest of the items start to click including the relays and the injectors. Try to start the car and the battery is dead. Charging now in the hope that it will start but no idea on what I should go after on this?

All suggestions welcomed. I don't want to tow it to my Indy but I need my car back to reliable. Been riding the motto to work the last 4 weeks but want my car to be there when I need it. Will post if it starts and runs again but still at a loss.
Thanks,
Sean
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91 745T M46