Hopefully @mary_watkins2002 will luck up and find some helpful advice on another forum while everyone here bickers and dickers over nuance and techno-verbiage.
Some crankcase pressure is normal. Thereās always a bit of blowby.
Ventilation of crankcase vapors into the atmosphere has been banned since the Clear Air and Waters Act was passed in 1970. These vapors have since been vented through the Positive Crankcase Ventilation (PCV) System, which allows the vapors to be drawn into the inductions system. The valvecover is no longer vented to atmosphere. This system contains a PCV valve the function is to allow passage of crankcase vapors into the induction system while preventing any flamefront from a backfire from traveling up the intake manifold and igniting the volatile vapors under the valvecover. Remember that prior to port injection, which did not become commonplace until the mid-'90s (some 25+/- years after the Clean Air Act) the entire intake manifold was filled with volatile fuel mix. There was a path of combustible gases all the way back from the cylinder to the space under the valvecover(s) when the intake valve was open.
It is possible that the PCV valve is gummed up, preventing the vapors from properly venting. That would not be uncommon. However, even if the PCV valve is fine, there will still be some pressure under the valvecover(s), especially on an old high mileage engine.
For the record, PCV valves are disappearing from modern engines. Multiport injection sprays the fuel into the engine directly behind the intake valve, direct injection directly into the cylinder rather than by the throttle plate. The volatility of the gasses in the intake manifold is nowhere near what it was with carburetors and throttle body injection. The only volatility in the manifold is that introduced by the crankcase vapors. A backfire wonāt travel back through the intake manifold to the valvecover space the way it used to. PCV valves are no longer as necessary as they were. I feel confident, however, in saying that this 2005 has a PCV valve.