1994 SAAB 900 stalling

Did he tell you which fuse he looked at, it well may be a bad connection in the back of the fuse holder.

Best get back to the mechanic and get him to have a close look at the circuit he was looking at, I feel that the problem is there.

Intermittent stalling can be one of the hardest problems to diagnose. With 150k miles on your car the electrical system has been running for over 5000 hours and is prone to some failure. When your car is in the failed condition you have to test for spark and fuel pressure. If your mechanic has narrowed the problem to your injection circuit. I would test for fuel pressure first using a mechanical gauge connected to the fuel rail. Get a reading of what it is when the engine runs fine and test it again when it fails. It could also be your crank angle sensor, they can fail after they get warm and work again once it cools off.

The crankshaft sensor is located behind the crankshaft pulley on the forward side of the crankcase toward the left. With the sensor unplugged measure the resistance between the sensor terminals, the resistance should be between 485-595 ohms or it should be replaced. It may test fine and still fail once it warms up.