Easiest way to check the fuel injectors is to listen to them. Use a long screwdriver held to the body of the injector with the handle pressed to your ear if you don't have a stethescope.

The fuel injectors get their power through the radio supression relay, black about 2" wide, 1" thick and 1.5" tall. You probably have two relays that fit this description, the second relay is for the auxiliary cooling fan. They are usually mounted together on one of the other shock towers, or a bracket attached to the coolant recovery tank. Swithc the relays and see if the problem goes away.

If you only have one relay, check for battery voltage on the connector to the injector. I think it will be the green wire, but not sure. There are only two wires to choose from so it shouldn't be too hard. The other wire (Gray?) is pulsed to ground by the ecu. All four injectors are in parallel and operate at the same time.

89schematic

Good Luck,

Dan