In the link I gave you to the '93 Toyota FSM(factory service manual) above, go to the section titled "engine". Under the 22re section look for the
"MFI System--Fuel Pump" , the steps to check the fuel pump on the vehicle are listed on the 3rd page(EGI-178).
Since you don't know the history of the engine, the install procedure the PO used, and the problem has been there from the start, I would inspect/check everything. The above FSM will walk you through it all, and has plenty of pics to help identify what to look for.
