Several quarts!!!! Wow. That really sounds like drastically high crankcase pressure. Bad head gasket or broken ring. If what you describe is true, then I don't think the PCV system is going to be able to handle it..
"It only does it when under power, not when idling" This is also kind of a clue as to what is going on. I'm betting on head gasket. Have the compression checked as advised earlier..Let us know.

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Jeff Lawrence
1989 300e
2000 Dodge Grand Caravan SE
No matter what you fix, there will always be something else to fix..
"Warranty" is just another way of postponing the inevitable.