GM Firebird 1982-1992 Repair Guide
Relieving Fuel System Pressure
Disconnect the negative battery cable to prevent fuel discharge if the key is accidentally turned to the RUN position.
Loosen the fuel filler cap to relieve the tank pressure and do not tighten until service has been completed.
Connect J-34730-1 fuel pressure gauge or equivalent, to the fuel pressure test valve. Wrap a shop towel around the fitting while connecting the gauge to prevent spillage.
Place the end of the bleed hose into a suitable container and open the valve to relieve the fuel system pressure.