2012 2.5L combustion blowby?

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2012 Mazda5 Touring; 2016 Mazda3 Sport
My wife was complaining recently of smelling unburned hydrocarbons somewhere near the car. Checking it over this morning, I discovered that combustion blowby is so extreme there's an actual breeze coming out the oil fill cap with the engine at idle!

I should really change the oil the next time I have time when the weather's okay, so it'll smell better then, but does it sound right to have so much blowby in the first place?

The car has about 78k miles and just recently started seeming a little peppier than when it was new, as if maybe it was finally getting broken in.
 
Puffing out of the oil cap is common to some degree.

Excessive amounts could be:

PCV could be stuck and forcing blowby out of the oil cap.

Engine could have worn rings allowing blowby past the piston rings into the pan.
 
I had a very similar issue - a hydrocarbon smell that wouldn't go away, excessive puffing out the oil cap (it should be a vacuum when the car is warmed up), all accompanied by relatively low compression. Check out my thread (link below) for more details, but changing the PCV alone didn't seem to fix things in my case, but trying to de-carbonize the rings with MMO and running the engine hard has fixed the crankcase pressure and HC smell problems.

 
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