not a mopar but need some help

hi y'all

this isnt a mopar and its brand X but i really need your help if your an automotive service tech or somebody who knows. i cant really afford to shotgun parts at this, and cant afford to get rid of this vehicle at this time. maybe somebody here has had this happen to a 99 chevy truck like this one, and can offer a way to fix it. so here goes with what i know, and what its doing and not doing.

the vehicle is a 1999 chevrolet suburban K1500 with oil leaking and oil burning 5.7 vortec V8 and 155,000 miles on it

it wont run, or more specific it wont run very well, i have to feather the gas, and it stumbles, stalls, and is hard starting, when it does idle at 1,000 rpm it idles smooth. when you can get it to rev up it doesnt pop or backfire so it hasnt jumped time

i borrowed an ECM from a friend who has a 1999 tahoe that was rolled, swapped the ECM, same symptoms, fuel pump makes a whirring noise when ignition is turned on, so i know at least this relay works, and ignition switch and the ECM switches pump on.

i do not have a fuel pressure gage or a code scanner, so i cannot tell if it has high enough fuel pressure, just know the pump is working from the sound. truck starts and idles smooth when it idles, but stumbles and stalls, and wont stay running, so i dont think its the crank or cam position sensors, otherwise it wouldent start, or would it?

i am down to 2 things i think it can be, either the fuel pump is still working but is not pushing enough volume and pressure, or the distributer module is going bad. was told not to get one of these from autozone as the china ones are junk, said if it that part thats badi should get a new delco one. distributer module from what im told has something to do with fuel pump, as well as spark.

my wife and i are going to buy a chrysler minivan next year, i just put new brakes, tires, and a radiator in this piece of crap to keep it road worthy. its my wifes car she bought years before we met, i want to kick this thing in the back door and send it off to somebody else but i got to make it last just one more year.

please help if you can
matt