Was it an OEM PCV valve? And I would think yes, It could be the PCV valve even if oem. In reading other problems of pressurized crankcases it looks like a bigger problem would be constant and not intermittent. Crankcase ventilation has been effected somewhere or pressure/flow has increased..
I would spend the very few dollars it takes to change the PCV and check the hoses. Do you have one of the blow by collection tanks? A crimped hose?
I would now think rough running would be cylinders/plugs cleaning out first thing at start up as oil has made it to cylinders or oil was clearing from throttle body.
Maybe a cleaning of MAF sensor would be needed also.
Sorry for long winded guesses, just trying to help.
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2003 Toyota 4Runner
V6 engine 4.0
Emission System
PCV Valve - Toyota (12204-31030)
2003-2015 Toyota PCV Valve 12204-31030 | OEM Parts
$ 4.45 . 5 bucks is worth the investment and rattle test is not always perfect.
Thank you
@
AuSeeker
for correcting me on the lifters.
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