Why would a 1994 Volvo 940 turbo station wagon conk out while driving losing power gradually then dies but continues to start up fine but when you drive it won't go past 25 mph and continues to die?

Sounds like your transmission is shot and the car won't go out of first gear. Then it dies to prevent the engine from blowing up. But don't take it from me - go to a Volvo mechanic.

Als Best Guess - Could be a clogged fuel filter. Enough fuel flow to idle but not enough to go.

Or it could be a Mas Airflow (MAF) sensor failure putting the injection system in limp home mode. Turn off the ignition, unplug the sensor and restart. If ir runs better but still has little power it could be the MAF.

change the fuel pump relay,