Its possible, there is an vacuum leak and if the egr is still connected....That the egr isn't opening/closing and thus not enough fresh air is getting into the intake....causing smoke...

What color is it?

I believe the smoke and oily valve cover are two different issues...

Low mileage examples, can suffer more wear then a high mileage example....from sitting to long, just going from home to grocery store etc...

There can very well be a large build up of carbon, that needs to be burnt out...with some high speed driving aka Italian tuneup(drive it like you stole it)...

Chances are, you do need injectors...at that mileage I doubt they've ever been changed, injectors that are peeing instead of spraying can cause a host of problems....from melting a piston to excess carbon build up...

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