My brother has a 98 durango 5.2 and when he hits the gas its like his intake is just sucking a crap load of air and the harder you push the gas the louder any ideas what it would be

 

Sounds like the fan clutch is seized... WITH the vehicle OFF, try to spin the fan... Is it hard to turn? Does it only do this on cold days? I think for the first few minutes of vehicle operation, this is normal... But if it does it when cold/hot/etc, then I say the fan clutch is seized...

 

I would look for a hose being off, sounds like it may be a vacuum leak.

 

He might have a K&N filter or none at all!