Where does the vacuum hose hook up to on a 1997 Oldsmobile bravada 4.3

SOURCE: shift motor vacuum line on dodge 1999 ram 2500

they have two lines from the axle they run along the front of the crossmember above the skid plate to the top of the transfer case on the drivers side

SOURCE: 1997 oldsmobile bravada making clunking

the vehicle has to be put on a hoist. turn the driveshaft that goes to the rear wheels,it is driven by a transfer case that is almost in the middle of the vehicle,just rearward of the transmission.
if the noise comes from the transfer case,then that is the problem.
the drive shafts for the rear have universal joints which can develop play and give the same clunk.
if it is the transfer case,it needs to have a gear replaced.
always warm up the vehicle for enough time for the engine to come down to 1000rpm before putting in drive,the fast idle is over 2000rpm,and puts alot of stress on the drive components,and over time wear them prematurely.

SOURCE: not sure where 4WD vacuum hoses hook up at

Isn't that an electronic motor on the case? If so then it's just a vent for the T-case. If not then it would go to a round ball canister on the fender.

SOURCE: where is the fuel pressure regulator on a 1997

it is located on the fuel rail on top the engine

SOURCE: 1997 bravada wont start

Hook fuel pressure gauge up to port near firewall. A battery charger sometimes boosts the vehicle voltage just enough to engage weak fuel pump. Should show 50-60 lbs all the time while cranking when not starting on battery.