Working down the checklist

I got the air side of things cleaned and back together and I’m still presented with the same issue. The car will start and idle briefly before stalling. Intermittently pressing the accelerator will sustain the engine for a second or so but ultimately it will stall. Since I’ve ticked “Spark” and “Air” off the checklist all that remains is “Fuel.” I believe this will ultimately mean fixing/replacing one or both of the fuel pumps. The main pump isn’t a problem as it’s fairly accessible. The in-tank pump will be a whole other ordeal as you generally need a special tool to get the cover’s lock nut off. It’s also possible that the fuel pump relay has gone. That would be ideal as it’s cheap and easy to replace. My Bentley manual should have testing steps, so my next move is to start there.