You may have a leaky fuel injector or a faulty check valve in the fuel pump. I vote for the faulty fuel pump.
Cheak fuel pression in the morning.
Try turning key to "on" position without starting vehicle and leave on for about 5 seconds. Do this twice. May prime fuel system
small evap leak, check the fuel cap, if it is not loose, replace it.
Give the fuel pump a chance to prime the system first.
the fuel filter is located inside a fitting on the carburetor, where the fuel line goes into the carb....hold the fitting with a 1" wrench while you break loose the fuel line with a 5/8 wrench, unscrew the fuel line and then break loose and unscrew the fitting
The fuel pump should be replaced.
EVAP Emission control system leak (small). It could be as simple as a loose fuel cap.
Where is the fuel filter located on a 1990 chevrolet blazer?
Your fuel pump is in the fuel tank!
The fuel pump for the 1990 full size blazer is located inside of the fuel tank. If this model does not have an access plate in the floor of the blazer then the tank will have to be removed to get to the pump.
power for the fuel pump goes through the oil pressure sender so if you loose oil pressure it turns the engine off. Look at the oil pressure sender and the wire for it.
A failed lift pump ( very common ) or a leak/break in a fuel line.