I also thought about the possibility of worn valve stem seals due to GM shitty valve guides. Just looking for anyone with experience of this or any other ideas

 

Telltale way to rule-out valve-guide seals is to see if it puffs smoke upon startup...if so, they're probably in need of replacement.

 

Do you run a full synthetic oil? any engine is designed to burn a small controlled amount of oil in order to keep the combustion chamber lubricated and to provide a more perfect seal for the rings, however a synthetic oil is known to burn and leak more due to its molecules being much smaller especially in higher mileage engines. my 04 2.8 with 207k will burn a full synthetic but a synthetic blend is within the oil consumption spec set by GM

 

This seems to be what it is. I swapped to Dino oil and the slight smoking is gone.

 

I've been running full syn but I'm due for a change so I'll try running syn blend high mileage just to see what happens.

 

What color is the smoke? White or darker gray?

 

White I think. It's a very small puff only at-high rpm. It really hard to see

 

However I will still probably run full syn. I can deal with a small amount of smoke. Just wanted to figure out what was causing it

 

These engines were built with substandard pressed-in valve guides. As the guides wear out the valve seals also fail. You will need a valve job w/new guides and seals. A compression test will prove the need for a valve job. A good machine shop should do the head for about $300. total. If you can do the labor the other parts required (timing set, gasket set, water pump, head bolts, damper bolt, fluids, & filter will be about another $400. A special damper puller & installer will also be required. Your rings should be good for at least another 100,000 miles. I recently did this on my 2004 3.5.