Check your relays first, RSR and FPR failures cause all kinds of fuel system related issues. Note that these cars (88-90 760's) have the "960" style square FPR's, unlike the rectangular relays found in every other 700 series car.

Is it like that all the time or does it getter worse as the car warms up? Do ambient temperature changes have any effect on the onset of symptoms? My 760 would start to hiccup as if there were air bubbles in the fuel line after about 30 minutes of driving at 75+ F weather and eventually it would stall out, play dead for 10-15 minutes and fire up again. After I cleaned my AMM connector the driveability of the car improved greatly.