okay I'll look into that. One thing to note, I doubt it's my issue though, I didn't tighten the new plugs with a torque wrench. Never have on a car [just found out that it's suggested to torque them down to a specific pressure(?)]

How do I do the compression test? Car running, pull one plug at a time, stick hose in, get reading, put plug/wire back in, on to the next?