Either the fuel pump isn't getting power, or is junk, but i would like to test before i replace the fuel pump. what i need to know is which color (pink, orange, yellow) wire is the power tot he pump.

A fuse won't fix anything if has blown

Check all the fuses

I would think the fuel pump has worn out & failed,
or you have rust & corrosion on the wiring,possibly
on top of the fuel tank & hard to get to

First check to see if a fuse is blown left side of steering column lower dash door. If fuse checks good remove the driver side kick panel for the fuel pump relay, a small plastic box with wires entering it. Raise the hood, disconnect the negative battery cable, then remove the relay. A good parts shop should be able to check the relay. If it's faulty, replace it. If not, test the wires leading to the fuel pump for power and replace or splice any where the power supply is broken. If replacing the the relay and checking wiring doesn't fix the problem you'll need to check the fuel pump which is located in the gas tank. This involves dropping the tank and removing the pump for testing. Relays in the Mazda pickups are the usual culprit. If none of the above works, the vehicle computer may be shot, and not a cheap fix. Mazda a in the late 80's to early 90's used Mitsubishi computers which are notorious for failing. Rebuild: $200. Used $60-150. If you need a new computer, go for the rebuilt, since a junk yard replacement could fail as well if it hasn't been previously rebuilt.

firstly remove the fuel pump from the tank and test it by connecting the leads from the pump to a 12 volt battery....if the pump turns on then test the wires running from the pump to the front of vehicle.....since you have replaced the relay then that is not the issue also some vehicles have two sets of fuse blocks instead of the standard one ......does the pump spin up at all when you turn your key to the first position without starting the engine? if it does then you need to test the fuel pressure getting to the intake....i replaced a pump recently that was only pushing 8psi to the engine instead of the needed 52-66psi new pump fixed the whole issue

Obviously no power to distributor or pump when key is turned on, check ignitin circuit and fuses related to pump and distributor

Try banging on the fuel tank, and then quickly try to start it, if it starts your fuel pump is almost dead and will need replaced soon.
If it doesn't start, test for power at the wiring connector on top of the fuel tank. This test requires 2 people, because the fuel pump is only powered for a few seconds when the engine isn't running. If you have power, then the problem is in the fuel pump (completely failed or bad wiring connection on the pump/inside the sending unit)

Well, to start with, there are a whole lot of things (including a bad fuel pump) that can cause a cylinder misfire. A misfrire code does not mean that you automatically start replacing ignition coils.
The fuel pump is not supposed to have power to it any time the ignition switch is on. It will only have power for about 2 seconds to "prime" the injectors, then it will remain off until the engine starts and gets over 500 RPM.
Did you test any of the ignition coils to see if they were in working condition before you replaced them?
Did you test the ECU relay to see if it was functioning properly before you replaced it?
If the mechanic was able to scan the ECU and get codes ot of it, the ecu relay HAD TO be working at the time...WHY did you replace it?

ECU failures are extremely rare - especially on Nissans. However, poking around in the engine control circuits without knowing what you are poking on is a REAL GOOD way to GET an ECU failure!

I recommend that you read the following article and get back to me if you need further assistance:

What Else Could Be Wrong?

check relays/fuses first then the pump if you know how to test it
the pump is easy to test locate any fuel line unplug it tell a friend to make a quick one key turn if squirts fuel then pump is fine
but check the pump relay first to make sure and to begin with simplest
it seems you can tell it is the pump but you don`t know where to start

try cleaning the connector that goes to the fuel pump, sometimes they corrode on inside. If that does not fix, test the wires feeding fuel pump with a multi meter until the condition shows itself again, if voltage drops to zero or very low then wiring problem, if voltage is unchanged with problem and fuel pump is not working and connectors are all clean, try replacement of fuel pump.

of course, check fuel pump fuse and relay to start, next, you need to test the plug at the pump with a test light, if it has power to the pump, the pump is junk, if not, there is a short or break in the circut. that means chasing the wires, a fox and hound is very helpfull with that..........