Misfire and hesitation at low throttle

CHTS is good, subharness is also OEM new from Nissan.

ECU gives MAF and fuel temp sensor codes. I've tried another yellow max and blue maf but they didn't seem to change anything. Still, if anyone has a known working yellow sticker I'd be interested just to make sure.

I think that the fuel pressure regulator might not be working, so I'm going to probably go ahead and get a new quality one just to make sure. I could put the old one on but the behavior didn't change. Anyways, just to give some more information I drove the car around for a while yesterday and the car wouldn't idle, especially if I let off the throttle while rolling, then depressed the clutch. Also, after a while it would misfire much worse when hitting the accelerator, resulting in a major loss of power. Not only that, after parking there was a good amount of smoke coming from what looked like the bottom of the passengers side exhaust manifold.

Use a handheld vac Pump & make sure that the fpr hills holds vacuum

Have you done a compression check yet? I must say I am impressed that you are actually going through with all this work to diagnose the problem. Most newbs would have checked out at the thought of making sure the plug gap was correct, and bought a S13. Compression check is pretty simple to do. Borrow a gauge from a parts store if you don't have one.

Just to verify, when you haul ass in this car, everything is fine and no misfire?

Cylinder 1: 175
Cylinder 3: 175
Cylinder 5: 170
Cylinder 6: 175
Cylinder 4: 185

Wait for it…

Cylinder 2: About 50, and I tested it four different times.

So, I guess that's going to be the major problem then, everything else would have been secondary. I'm still a little confused because it seemed to run okay and have enough power when I would keep it in the higher RPM range, but obviously it wasn't working at its full potential. The noise may have prevented me from hearing the misfire at that point I think. I probably should have run a compression test sooner, but I didn't think it was running poorly enough to be essentially on 5 cylinders. Well, at least I know now, I should have gone ahead and done this sooner and it would have saved me a lot of effort. Still, I now have a much better idea of how everything on a VG30 works, and plenty of new stuff for the new engine. Anyways, I suppose I won't worry about finding out whether it is a ring or valve issue, because I have that other motor to put in anyways this summer. Once I pull this one, I'll may see what's wrong or I may not, since I have two spares.

Thanks for all the help everyone, it has been interesting.

I won't have time to start the swap until this summer, but I'll probably need advice on the rebuild. I have the motor that was supposedly recently rebuilt and looks like it, but I need to rebuild the T3 I have and replace whatever else I should go ahead and get to while the motor is out. But that will happen later.

As an aside, I ended up with a Z31 because I wanted an old school (cheap) Nissan and couldn't afford the S13. But now that I've had one (or three), I would buy a nice Z31 over an S13 pretty much any day. Too much ricer and drift tax, whereas the Z31 is more classy and unique. Still, it is fun every once in a while to drive my friend's 89 S13 coupe.

Do a cylinder leak down test that will help guide you to the next step

I'm not that worried about it, I'm probably going to swap in the spare engine that I have and then I'll think about fixing this one.

Awww shucks kid. That's a bummer.

Above 1500rpm or so, that 50psi turns into over 100 because it can't leak compression fast enough at that speed. Then it will actually start running right.

I just read through this whole forum in my wine class. I can’t wait to get my 84 running proper. Till that day, I will be on the hunt doing more research. Thank you guys for all this extensive work, it is truely appreciated.