same symptoms again!

Well I'm back again with the same symptoms. I changed the intake manifold gaskets for my oil consumption problem. I drove the truck 300 miles and didn't use a drop. I thought I had the problem fixed. Then I drove another 100 miles and am down 1 1/2 quarts. There are no more black streaks on the side of the truck next to the exhaust, and the spark ping is gone, but I have a great loss of power. I know what the cat does when it goes bad, I just changed it about 5000 miles ago, so I don't think thats the problem. Is there a valve of some type or something else I am overlooking that would cause the oil consumption and the drop in power. (I can still do good on the flat, but it falls on its face on a hill).

How many miles and what engine on your truck again? Does it seem ok at high rpm, or is it weak at all rpms?

Is your oil filter on correctly?

The oil problem was caused by a plugged cat. This time it was because of the oil. It was under warranty and was replaced for free. Now the power is back, oil consumption gone, and so is the truck. They gave me a new 04 quad cab with a hemi to drive while mine was getting the new cat on, and I had to have it!