uncre8tv

Hi - noob with a problem already, I'll start my tale from the beginning:

Bought a 1989 S4 5spd yesterday, interior had minor issues, paint is heavily oxidized, but it seemed to run good, stop good, turn good, and during the test drive, started good too.
Drove it home ~60 miles with no surprises and one uneventful stop/start for fuel.
Parked it in drive way, moved it into garage a few minutes later, again without issue.
This morning I get a roar but no start. Smell is telling me there is (some) fuel, the roar is telling me there is (some) fire. If I stand on the accelerator it I can get a few cycles of roar, fade, roar, fade, stumble, die (20 sec total maybe) and if I don't stand on it I just get roar-die.
If not for the fuel smell I'd guess I wasn't getting gas, but I hear the pump with a 2sec healthy buzz.
Given that it did run/start warm yesterday, I'm wondering if there is anything temp-related in the FI system that would preclude the fuel pump running after catching?

I did try searching here and elsewhere, but couldn't find the exact symptom set I've got here. I welcome any pointers for future searches if I'm missing an old thread that would apply.