You can start by getting it running, with the misbehavior occurring. Now, one at a time, unplug fuel injectors, note behavior and plug back in. When you pull a functioning injector, the idle should drop briefly, and then recover. When you pull a non-firing one, there will be no change. If you find a bad one, the next step is to stop the engine, and swap the plug of the bad one with its nearest swappable neighbor. Restart, and unplug each of those two. If the problem follows the plug, it's a wiring harness or computer problem. If it follows the injector, it's a bad injector. I've had problems, and heard of others also, in a 93 with a defective wiring harness splice, causing similar symptoms. If you find the harness is bad, check (engine off, ignition off) with an ohmmeter, on the common (+) leads to the injectors. They all feed off a common source at the ignition module. The positive side is hot whenever the ignition is on, and the computer switches the negative side of the circuit for each injector. I think the wire is orange and black. You can test this easily enough. Find a terminal on the ignition module that gives you a zero ohm reading to one side of an injector. Now check from that point to the same side of each injector plug. Any resistance is a no-no. It will tend to get worse as the engine heats up, so sometimes these symptoms will come and go. It may be good enough to fire the injector when it's cold, but reach a critical point when hot. If you find nothing on that side, check with an ohmmeter the wires going from the injector plugs to the computer, and also check the pins on that plug very carefully for looseness, etc.
If the problem is a bad harness splice, you can just slice open the harness and solder a piece of wire in to bypass the splice. I went through this with the 93, spending days on diagnosis, and many many dollars on tuneup parts and even a junkyard computer, before I found the problem. It took about 20 minutes actually to fix it once I found it.
Getting back to the original running test, some injector plugs are harder to pull than others. I'm not sure what years, or circumstances, change this, but if yours have little metal spring clips in them, they can be very hard to pull. It may be helpful to remove all the spring clips before the test, and put them back in later. Anyway, practice pulling them first.
