backstory: i bought this car with the intention of a quick flip. boy was i wrong. blew the motor about 8 hours from home so i bought a used (running) motor and threw it in, but it the engine runs rough and i can’t pinpoint the issue.
end backstory

what i’ve done:
new plugs and wires
new distributor cap and rotor bug
new air and fuel filter
new fuel pressure regulator
compression test brought back 145 across all cylinders after 3 cranks
reset the timing belt
ignition coil showed .8 ohms
all injectors showed 14.6 ohms i believe? (been a minute) but they were all the same
cleaned maf
all fuses looked good
about 15 hg of vacuum
now i’m officially stumped. car will start up and idle for about 3 seconds then stumbles and dies
please help </3

 

Not enough fuel flow?
Fuel pump could be weak or isn't connected properly (in-thank)?