Hello Buddies!

I need some help!

I have a 1987 Astro van with the 4.3 v6 engine.It is used for short trips, mostly city driving and has very low miles for the age (about 50K), but about 3 moths from now, it suddenly begun to eat the oil at the amazing rate of one quart every 25 miles! There is a lot of white smoke at the exhaust at heavy acceleration, none at idle. Of course it fouls the plugs, so non-foul adapters were fitted, just to keep it running.

Amazingly, the power is not affected, it runs just as always! going uphills with no effort, even towing a trailer with two dirtbikes.

Check engine light does not come on, diagnose scanner tells everything is OK!

What is wrong with? I guess this is going to take a huge part of my christmas bonus, but want to be sure what to do!!