Here's the details.
'94 Civic Coupe, 1.6 D16Z6, APEXi VAFC VTEC/AF Converter, Megan header, Skunk2 adj cam gear, typical cone filter/air tube, no cat, "High Output" replacement coil, MSD Ignition box. (non-turbo)

The engine recently... around the last 2,000 miles or so, began to stutter a little when accellerating from below 2,000 RPM. If I'm at say.. 1,400 RPM , no matter what gear, the engine will buck once... maybe two or three times until it's over 2,000 RPM. Once over that, it runs fine. The harder the throttle is pressed, the harder the bucking. I have watched the APEXi Turbo Timer. It has a numeric a/f ratio mode. It isn't going too far either way. It tends to stay right around 14 to 14.5 until the VTEC kicks in, at which point it tends to float towards the high 13 range. The car had a turbo on it, but it was removed before I bought the car. A standard head gasket was put back on it. It has done fine before, but has started this recently.

I have yet to pull the spark plugs and I'm considering that they may be fouled or worn. It just surprised me. The wife drives the car daily 40 miles one way to work and it sees mostly open county roads. Very little under 2k. I'm thinking ignition hickup, possibly related to the plugs... whose condition is honestly unknown at this point anyway. We've had the car about a year now. The Civic is a second car, and not really a toy for me. It may be some day, but for now, it's pulling long-haul duties.

It pulls hard once it's over 2k, but even below 2k, it still feels strong until it kicks, or bucks on me. I don't like it. Anything other than plugs or (potentially) plug wires I need to inspect. Not sure if there is some model-specific trick or component to be aware of.