Pull the air cleaner assembly and look around the MCU(mixture control unit). This is the air speed sensor + fuel distributor. I say this believing you have some sort of CIS fuel injection(constant injection system). Look for leakage. Also look around fuel injector connection points. If nothing here, pull your spark plugs. Are they wet and somewhat sooted? If so, your mixture is off. I do not know if Lambda closed loop was controlling things in '87.
Charles Probst wrote a good book on Bosch Fuel injection principles. Amazon.com carries it. Buy it. You'll learn all sorts of good things.