weird noise

theres a weird sound coming from the dash on the passenger side when i'm accelereating at low speeds. the sounds is there when i'm in park too. its like a little rattle/gurgle noise thats driving me nuts. if you know what it is lemme know!sdf

Does it happen when your A/C is running? Sometimes the A/C system can have bubbles in the lines which is normal but, if it gets worse then you may have a leak.

Alternately, I wonder if it may be your heater core and it could have some air in it????

I had the same problem with my 99 5.3!

Turned out to be a low coolent level in my reservoir container
by about 1 inch.

Allow the truck to cool "completely" over-nite, and then add up
to the line marked "cold full"
You may have to do this accouple times until all of the air has been
burped from the system.

Make sure the antifreeze has been properly mixed to the right
hydrometer level.

-Mike