Missing after vacuum leak test..

[ngbizzy09]

Well I have been trying to track down some of my hesitation problems with the Z, so i decided today to pressurize the intake system to find any potential vacuum leaks. I pressurized to 5-6psi like the write up says and found the balance tube leaking on the passenger side.. fixed that and tested again and couldn't hear any other leaks, other than what sounded like air escaping through intake/exhaust valves which i confirmed when i put my ear up to the tailpipes and could hear air escaping.

So I then started to reassemble everything and noticed some green slime and seeds?? in the maf, not on the sensor part hanging down, but between the screens so i carefully blew out the crud the best i could and continued to reassemble. SO.. then i start the car, and its missing at idle.. wasn't before.. ugh.. so I did a power balance test to find that the passenger side front (towards front of car) and middle coilpacks/injectors can be unplugged and the idle doesn't change.. So i grabbed a screwdriver and the injectors are ticking away when hooked up so I'm thinking wth?!?!

I decided to take it for a drive to see if i could get it to clear up, and i found that it still has plenty of power and doesn't present a noticeable miss up top, but when idling it will barely stay running and is definitely missing.
Where should I start?

[ngbizzy09]

So a little bit of an update here.. I confirmed today that the whole passenger side is not firing. I have checked for spark, it has that. And it is getting fuel because my cat got so hot today it started smoking. Also checked compression and it is excellent. So I am getting fuel, ignition and air.. what could be causing half of the motor to not fire? Is it possible that I am getting a poor spray pattern? I also found that if I wiggle the cas connector, I can get the idle to slightly improve or worsen but who knows with that because my connectors and harness arent exactly in top notch order.. I just don't understand what I could have changed when I pressurized the intake to cause it to go from idling fine to running on 3, and all on the same side of the motor none the less..

[nissanfreak12]

Check the PTU, either for corrosion or loose connections.

Also could be sticky injectors, test them to also rule out if they are bad. If they test good, possibly some cleaner in the gas tank could help them out. Had one that was sticking, ran seafoam, not sticking anymore. Doesn't work for everyone.

[ngbizzy09]

How could the ptu be a factor when I am getting spark on all of the cylinders that are not firing? I have also done the injector cleaner and I am not getting any change yet.. any other ideas? Again, just for clairification, I have spark, the injectors are ticking and ohming out at 12-14 ohms, but the cyclinders are not firing.. what else could cause them to not fire?

[nissanfreak12]

When someone says not firing I automatically assume its not getting spark, my bad.

If you are not getting one whole side of the engine "firing", you have either timing issues or compression issues. That's in fact you are getting air, fuel and spark. Have you done a compression check? Have you checked timing belt? When was the last time the belt was changed? Its very possible the timing jumped or when you tested for vac leaks, you may have given it too much pressure and not realized it. Just trying to help.

[ngbizzy09]

Compression is fine. Is there an easy way to check to see if the belt has slipped? And the belt was put on about a month ago.

[ngbizzy09]

Is there any damage that over-pressurizing the system could do to cause this miss?

[nissanfreak12]

Over pressurizing could push out/blow out orings, especially with and deteriorating ones. But you have good compression, so I am more leaning to timing. Even then that should throw off the compression test.

Only way to do it is take the covers off, and count the cogs between the indention on the gears. Maybe someone else will chime in, but something still isn't adding up. What numbers did you get for all the cylinders?

[ngbizzy09]

I would just like to update my situation.. I took my car to an import specialists shop where they determined that injectors 1 and 3 needed to be replaced. Well they replaced the injectors and the dead cylinders stayed dead.. so needless to say, 250 dollars later I still had my problem. So I proceeded to investigate further into possible causes for why the whole passenger side bank is not firing.
Things I have checked are:
Compression.. on 1 and 3 I am getting a solid 180psi but on 5 I am getting 140ish..180 seemed pretty high for an engine with 157xxx and 140 seemed kind of low so that was the first abnormality.. so I proceeded to check 246 and all ranged between 155-170; I found these numbers to be more believeable. This led me to think timing may be an issue so I tore off the covers and checked everything out. The intake and exhaust gears on the passenger side appeared to be off a tooth so I got excited and quickly reset to belt, triple checked everything and then checked the compression. Again two 180s and 140 but I figured ah what the heck lets start it up and see what happens.. yup still runs the same..
So this is where I'm at, I have verified that there is spark on all of the cylinders not firing. The import shop installed new injectors into cylinders 1 and 3 because those were initially the ones that were dead, that resulted in no change. So its not spark and its not fuel injectors. I have verified that the timing belt is correct so its not that and it has compression.. so I have everthing for combustion but its not there!
Idk.. I'm giving up at this point.. I have so much money and time invested in this car just to get it running right.. I might just do a motor swap.. who knows.. I'm sorry for the book, but I just had to vent.. if anybody has any other suggestions I will gladly welcome them all. Other things I have tried are swapping ecu's, checking the CAS to ensure the teeth are all there and half moon shaft is ok, probing injector harness for 12 volts and making sure they are ticking with the screwdriver method. I swapped spark plugs from side to side with no change.. wiggled PTU, MAF, and CAS wiring no change. Checked to see if the dowel pins had sheard off the can sprockets because I've read about it causing similar problems.. I've got to be overthinking this, what am I missing? Thanks if you made it this far haha
EDIT: I also forgot to add an important detail.. number five cylinder, the one with 140 compression, comes and goes while 1 and 3, the ones with 180psi are solid dead.

[ngbizzy09]

Can anyone explain this one to me...? I decided to try unplugging the injectors on the drivers side, which should have caused the car to not run at all because the passenger side cylinders aren't firing. So to my surprise, when I did this, the passenger side cylinders start firing. So I'm like ok?!? Then i plug the drivers side injectors back in hoping it will run on all six and I found that it sounds like it is still missing, but upon unplugging the passenger side coil packs, it changes the idle.. WTH?!?! can someone explain how this could possibly be happening??