Intermittent Misfire

As a test with the engine running at idle, squeeze the PVC-hose shut for a moment.
See if the miss disappears.
Idle will usually improve while doing this nonetheless.

Could be a lean mixture, or one or two cylinders getting a lean-mixture. Perhaps the PCV-system host is connected wrong, or brake-booster hose is connected to somewhere on the intake manifold, instead of to the appropriate port on the carb. Usually a rear port).