What causes excessive valve cover pressure?
 

I have a 99' honda accord vtec 2.3L. The oil cap when taken off puffs alot of air, the pcv valve is newly replaced. What could cause this excessive pressure that causes the car to run bad and oil leaks? Need help, thank you!

possible piston ring bypass, unsusal or excess valve guide ware, most are from high milage engines. pcv valve changed but have you checked the hose and where it reenters the throttle body or intake manifol, it may be clogged.

The pvc sucks pretty good it doesnt seem clogged.

check the rest of items on the list. try a compression check to see if you have any low cylinder pressures. what is your milage on the engine? is your hose clear, clean, new. is the manifold fitting clear.

Car has 128k. My uncle and I are in the process of taking the head off and going to take to a shop to get resurfaced and to check valves. Hopefully its just a stubborn valve not piston rings.