92 300zx misfire

[toms92300zx]

Ok so I have a problem. I see it's apparently a common problem. here is my question. I have a misfire on cylinder 2. I discovered this by pulling off coil pack wires til I noticed no change. I tried swapping coils and then tried swapping spark plugs. Still misfire on cylinder 2. I checked compression and compression was good. all my research is pointing to either a bad PTU or a bad fuel injector. My question is what is the easiest way to tell which is the true culprit. I'd hate to tear apart everything to replace a injector only to not solve the problem. I haven't seen anything on line that tells me how to check the PTU. If you have any ideas on how to tell for sure or how to check the connection at the coil pack to even see if that connector is getting a signal. I'm in dire need and cant afford to buy every part it could be. Thanks

[speedeast]

Easiest thing is the check the injector. Pull the connector off of it, and place each probe of a multimeter on each prong of the injector (engine off) and check its impedance (ohms - 20). It should be around 12, but i think it'll pass between like 11 and 14.

Here is a reference that will shed a little light.
http://www.mdsmarthome.com/z/Z%20Tech/Z ... Method.pdf

You also need to formally check for spark.

[toms92300zx]

so I ohmed out the injector and it is at 12. I checked for spark by pulling the coil out while car was running and the spark seemed there but weak. I almost think it's the connector to the fuel injector, but if that's bad where does that go back to. How do I check the connection on the other end? I am trying to get a noid light to double check but now I am really frustrated. Does anyone know anything about the PTU? I've replaced the CAS before but would that cause just one cylinder to misfire if it went bad again?

[the converted]

If you have a weak spark I would be checking the volatge to the coil and the ground wire to make sure that there isn't any corrosion.