94 E320 cabrio noisy fuel pump and hesitation when starting off.
 

The fuel pump seems pretty loud whenever the engine is on, but when taking off from a stop, it quiets down for a second and the engine hesitates. Otherwise it runs fine. Starts easy hot or cold and cruises at 70. Fuel filter replaced 1,000 miles ago. Would connecting a pressure gauge and taking it for a drive show anything?

yes 4-4.6 bar or approx. 55 psi 60 with vac line to pressure regulator disconnected