[rjacket]

First thing after experiencing a problem after doing some work is to suspect the work you did itself not a new area that wasn't a problem before!

You changed the oil filter! Where does the oil from the oil filter go when you remove it? On the exhaust!

What would happen if you didn't put the oil filter in correctly? Eg double gasket or too loose? It would leak. On the exhaust! Causing smoke. It might even drip onto the ground.

What would happen if your new oil filter is poor quality? It might leak. On the exhaust! Causing smoke. It might even drip onto the ground.

 

[rjacket]

I've read people's comments saying we should change the Duratec PCV valve every year because it's prone to clogging up and blowing out the gaskets.

Well if what "people" say is so reliable did you find any "people" saying that valve cover gaskets would blow out a few miles after an oil change?

 

[rjacket]

I picked it up this afternoon and while driving home though the acceleration seemed peppier than before. Was it my imagination, or would replacing those gaskets and the old PCV improve engine performance so noticeably?

Maybe. Did they air your tires as well?

 

[rjacket]

Maybe but they only replaced the PCV itself. I'm hoping that if the PCV was clogged this would help reduce pressure on the gaskets.

Well you could ask your mechanic if the old one still rattled.

Your Taurus was looked after by the previous owner. They changed the transmission fluid and filter at 100k. They probably changed the rear spark plugs and pcv valve at that time - I can tell from your picture in this thread that the intake manifold was removed.

So you got quite lucky and inherited a well looked after Taurus. If gaskets need changing now it is simply the passage of time or how you have looked after it since you got it eg you didn't touch the transmission fluid for 90k miles until you got a warning light.