Lots of good recomendations here but, I'd go back to basics first.
Try doing the PVC and then some regular motor oil(dino) changes for a few Oil Change Intervals(OCI). Maybe with some Quaker State Green Bottle(QSGB), Valvoline White Bottle(VWB), Pennzoil Yellow Bottle(PYB), or any Dino oil of your choice. I am a fan of PEAK Oil too when it's a good price. These Civic's usually aren't fussy about oil. Although, lots of Wide Open Throttle(WOT) and higher RPMs can also use oil in any engine. Maybe try some 5W30!
My daughters Mazda3 2.0L requires 5W20, with no other recomendations in the Owners Manual(OM). I often use 5W30 without any MPG penality and the engine is quieter/smoother and overall the engine seems to like it just fine.
And yea, Civic's have no balls! But, what I have noticed is, the Civic will come into a different light at >80 mph and beyond!
I've had Civic's and know tons of folks with them. They all run regular motor oil and have many hundreds of thousands of miles on them.