Car is a 95 Si with a more or less bone stock d16z6 with 281000km. No CELs. Has a short ram intake but thats about it.
Basically whats been happening is the car will stutter at low RPMs and feel like it doesn't have much power. Every now and then it will let out a nice pop if you give it WOT at lower RPM. Once it's over 5 grand it seems to run fine.

So far I've replaced the plugs and gapped them to stock, checked the timing, it was out but now its at 16degrees and the problem remained. Changed the PCV, new cap, rotor and plug wires. Purged the fuel system and new fuel filter. Checked the grounds and they all look good.

As far as I can tell the fuel pump seems to be fine and the fuel pressure is normal. I'm going to swap out the dizzy tonight with a known good one and see if it helps. Maybe try a good battery too.

Could a vacuum leak cause a misfire of this nature? It idles perfectly fine. I'm almost to the point of bashing my head against the wall trying to figure it out.

 

a spark tester that you can adjust the spark gap on will help you determine if you have good enough spark. I would be looking at compression, and did you actually get a fuel pressure reading or you just think it is good cause it idles fine. the other thing I would do is get a reading off the 02 sensor to see if it is stuck lean or rich and help lead you in the right direction.

 

I have a very similar problem with my car, sometimes it runs perfect, other times out of nowhere it just starts misfiring and running like crap. Let me know if you figure out the problem. You can see my post here:

https://honda-tech.com/forums/tech-misc-15/pre-existing-problem-went-b18b-b20b-2434084/