can you test an ecu(computer) for a 1991 3.1 with a multi-meter? or anyway at all? if so how?

 

The short answer to that question is NO. The long answer is that if you try to test the ECM in any way and it is still good at the moment, it won't be when you are done. Pretty much all you can do is to check to see if the ECM is providing ground by using a test light connected to the positive side of the battery on one end and the wire you are testing on the other. The light will light if the ECM is grounding the circuit. Oh, and an easy test? Does your SES light come on when you turn the ignition on? If so, you know the ECM is getting power and ground.

:edit: You really should condense your posts so things don't get so confusing.

Anyways, it almost sounds that you don't have fuel delivery (not supply... I'm talking injector pulse, not fuel pump), but that won't affect spark. No ignition affects fuel delivery. If everything in the ignition system has recently been replaced, what is left to look for is broken wiring somewhere in the system. Make sure you have pulses from the pickup coil (just a resistance measurement won't help you here). Set your meter to the VAC scale and look for about .2VAC coming out of the coil wires (one probe on each pickup coil terminal, not to the battery or anything else... it won't help you if you don't do it right).