weak fuel pump.?

hey is it possible to have a weak fuel pump .? and if so. is it possible to test without removing any of the fuel lines.? my car lopes while at idle and then when it downshifts to what seems like 5th gear. to go up a big hill i have to get knee deep in the throttle. its a 1991 buick regal. 3.8 automatic tranny. with a new fuel filter and total tune up.

Your Regal should have the VIN "L" 3800 so there should be a Schrader valve located on the fuel injector rail assembly where you can test fuel pressure with an automotive fuel pressure tester. Look for a black plastic cap at the front part of the fuel rail towards the left hand side. You will test the fuel pump and fuel pressure regulator.