Fuel shut off switch 1993 bravada - 1993 Oldsmobile Bravada

Internal pressure regulator on the fuel pump should hold for about a minute but some pressure loss is normal. However, on initial start-up, the pressure must be at operating pressure or the system wont work. I suspect the fuel pump is failing, it is an all too common problem for GM trucks and SUVs with mpfi fuel injection.
IACs do not go out very often, usually there is a problem with vacuum leaks, dirty throttle assemblies.

Here's the link and I'm sure you will get the solution of your problem
OLDSMOBILE BRAVADA OWNERS MANUAL 1993 2004 DOWNLOAD

hard brake pedal and the engine is idling rough usually indicates the power brake booster has gone bad. the booster has vacuum going to it from the engine so if the diaphragm in the booster starts leaking then it affects engine performance.

I'm guessing from your short statement that you are not getting fuel. Your '93 would have either the 2.8 or the 4.3 v6. If your not getting fuel, check the fuel pump relay, look for a blown fuse. Disconnect the oil pressure sensor and jump across the connector terminals and try to start the engine. If the oil pressure sensor is bad, it will shut the fuel pump off.

Under the vehicle on the driver side, below seating area, mounted on frame in fuel line,

the car will have an asd relay in the fuse box, (auto shut down relay), but get rid of that toggle switch, if you ever get a fuel leak , or in an accident the fuel pump won't shut off, causing a fire hazard, also nulling your insurance

1993 Bravada, look for any problems in the AWD system to make sure it's working. The CV joints and ball joints go bad on the Bravada's due to the AWD system. The year of the Bravada, inspect the fuel line. Fuel Line Prone to corrosion buy the drivers side rear wheel by the frame and inspect the brake lines. Other then that, everything else would be on your judgment as to corrosion under the Bravada under carriage like the rear tail gate ECT. Good luck and enjoy you new ride.

The sulfur smell usually means that your fuel mixture is too rich, and the catalytic converter is reacting with the excess fuel. You'll probably need to replace the catalytic converter along with the muffler, but get the fuel mixture problem fixed before you do that. Else you will ruin the new converter.

This activity is controlled by the Electronics in the ECU, If there are no coolant leaks, the coolant is filled, engine oil level is OK, then a normal restart should be in order.
Regards.DT

Check your fuel pressure at the Shredder valve, you should have 60PSI to 65PSI. If you have less then that or more then that your going to have problems with your fuel injection system. The other thing to is to check your fuel pressure regulator. Hook up the fuel pressure gauge and turn the ignition switch to the run position to activate the fuel pump. Once the pump stops pressurizing the fuel line wait and see if your losing the fuel pressure excessively. If you are then your may have a bad regulator and it's leaking internally. The other thing to is may be a bad fuel pump, The good news is the fuel pump in the sending unit in your bravada can be replaced rather then the whole unit. If it is the fuel pump, Buy a heavy duty pump to install to your sending unit. Don't have them sell you the whole unit, pump alone is around average $60.00 other then the whole unit for $230.00. Good luck and keep me posted, be glad to help