[sm=smiley20.gif]What he said.

 

Depending on how often you change your oil ... a quart (or more) down is not at all unusual. All engines use SOME oil ... but if it's full when you check it on Saturday and a quart and a half down on Friday ... you've got a problem.

 

AAA4948 - I notice the same thing with my truck. Basically the same description you gave in the first post.It usually happens when going up a slight hill. I'm pretty sure it's just the noise of the air moving through the throttle body. Check for air leaks between the air filter housing and the throttle body as described.
With my truck, it is more pronounced since I have a 14" round air filter. It was very noticable when I had the 2" high filter on, but got quiter when I moved up to the 3" high filter. I wonder if it isn't the Idle Air Control (IAC) opening up slightly under the load. When you step harder on the throttle, the IAC closes again since your butterflies are open more in the TB. That's just a guess, but I'm basing it on the noise being similar to the soundthe truck makes when it is idling after I first start it up. Bascially, its just the sound created when air is moving quickly through a small opening, just like having a window open a crack when the wind is blowing hard.

 

Thanks everyone. I think this is just TB air noise. My friend and I drove around the block in his truck with the air filter off once just to see if there was a difference. Same noise now that I know what I am listening for. Guess I got lucky with no problems again.

 

yeah, its the gasket on the TB, i have the same hissing between 2000 and 2500rpm, around 50-60mph.
tighten the airhat or replace the gasket.