drop a cap of oil in the cylinder your testing and see if that brings it up.

if so then it could be your rings.....


does it smoke? when u rip on it?

 

This. I've done this before and it has made all the difference in response/power. Without a wideband it is tricky to fully understand what the motor is doing as the spark plugs offer a pretty narrow glimpse into how things are running, even if you know all the places to check them.

most of the plug looks ok but the ground strap is a little on the white side. should have a touch more brown/tan colour than just slightly off white

 

White plugs = lean AFR

 

Maybe u just got used to the power...it never feels like it used to..
unless u go up..woot!