Nissan Repair: nissan 350 z issue, nissan 350 z, valve cover gasket

Question
My car developed a random cylinder misfire months ago and I have been down all avenues known to me and still am no closer to knowing the cause as I was when it began.  I checked spark plugs, coils, exhaust for dents/restrictions I have spark from all coils and plugs,  and I ended up emptying out both catalytic converters because the one on the pass.  side was pretty restricted, I also checked for any possible intake leaks and found the tube going directly into the throttle body was piched back under the clamp so I did have a 1/4 inch gap there, I fixed it at that time.  I did notice a little oil in cylinder 6 spark plug tube when I was checking out the coils and plugs and I know that I will have to replace valve cover gasket soon but there wasn't enough oil to harm the coil there either. I have replaced the pcv valve nand 2 oxygen sensors the 2 after the catalytic converters.  If you have any ideas what I should check next please send me your ideas or if you have this is something common or thay youve heard before and know what my problem is please let me know at your earliest convenience, I d really appreciate any help you may have for me on this.  Thanks

Answer
Francis,

I have a 350Z too.  I had the same problem you describe and it was a combination of the fuel pump going out and a couple of stuck injectors.  You can check which injectors are defective by pulling the spark plugs and observing which ones are really black.  The black ones are where the injectors are not closing properly.  The fuel pump pressure inspection is a problem since there is no pressure port to verify pressure.  So, Nissan has the tool or the aftermarket like Cornwell or Snap On tools.  Once you have an adapter hooked up to the fuel pump you can check the fuel pressure.  The fuel pump is behind the drivers seat and behind the speaker or blank cover and then under the padded sound mat.  Remove the cover and the pump is under it.