'01 Express Van Running bad and using a quart of oil per 250 miles?

[infoskoop]

I have a 2001 Chevy Express Van (97,000 miles on the Vortec 5.0).  Had a tune up less than 10k miles ago.  Recently it began running real rough and Check Engine Light came on.  Since prior to getting the tune up, it has been consuming oil (not leaking).  Originally, it was going thru a quart every 1500 miles or so but now, after a fresh oil change on Saturday and a subsequent 266 mile road trip, it is down a quart.

    Last week, I took it to the Chevy dealer to find out what's going on.  All plugs are fouled and they're getting misfires on all cylinders.  They kept it for a couple days and did some high powered type cleaner internally hoping to maybe clear up any carbon build up that may have been hanging up the rings.  Told me to run it for a while and see how it goes.  On the recent roadtrip, after 100 miles, Check Engine Light came back on and it's still running terrible.  Now they suggest possible ring replacement ($12-1500) or valves at .  Any suggestions or ideas?

[3DDD]

Could it be possible that someone has put sugar in your tank, that is what it sounds like. If you do not have one now,after you do all this repair, I would get a locking gas cap.

[toomarilyn]

As for a ring job -- All 8 pistons would have to be cracked for all 8 plugs to be fouled by oil and that ain't going to happen. Or you have got this engine extremely hot and tryed to cool it down to fast which could have caused the rings to lose their tention but that ain't likely either. The more likely cause would be the seals in the heads. Do compression check on each cylinder. all cylinder should be close to the reading of the others. 125-150 pounds.  Also if your burning a quart every 266 miles then its going to clog the converter soon. I'm  wondering why the chevy dealer didn't tell what computer code they got,  when the check engine light came on.