Fuel pressure regulator problems often exhibit symptoms of failure when fuel pressure gets excessive or the diaphragm in the regulator breaks causing fuel to leak into the intake via the vacuum hose attached to the top of the regulator. You can test the excessive pressure issue by installing a fuel pressure gauge to see if the pressure is too high. Should be in the 3 bar range (app 40 PSI)
One more way to test, (make sure you put the end of the hose is a bottle so it does not spill on something HOT!), is to pull the vacuum line between the fuel pressure regulator and the intake, at the intake end. Start your Saab. If fuel leaks out of the vacuum line, then your diaphragm is ruptured. Stop engine immediately. My advice would be to put some sort of small bucket or catch pan to capture any fuel from the vac line. Just my experience.