Civic EG

Can ya'll help me figure out a stuttering issue? B18C stutters slightly under load after being warmed up, usually cruising between 2500 to 4000 RPMs. I've swapped to a known good distributor, and swapped spark plugs and I still have the issue. Idles normally after warmed up, and has plenty of pulling power, no CEL, VTEC engages perfectly all the way to 9k. It smokes when revved, which I'm almost positive it's from the valve stems seals, which I have but need the tool for the springs so I can install them. I've got the full EVAP system hooked up still, but I get a little oil in the PCV valve area. Could either of those be the reason it stutters? What else would cause it?

Spark plug wires. Mist water over them at night, see if there's any arcing.

I forgot to update this: The issue ended up being the MAP sensor. Smooth as butter now.