99 gmc air leak

Yesterday i was driving my 99 gmc 5.3L Z71, and it made a huge air leaking sound, like i had air brakes. I stopped and it quit, i thought i blew a tire, but no flat, it did it one other time, but i can't find any leaks, or even know of anything that has enough pressure to make that sound. Checked everywhere underneath and no signs of leaks, fluid or air, no clean spots that blew air off, nothing. I have had a dramatic power loss over the past few months off the line. Can't even spin tires and it sputters. I had to floor it to get over a small bridge. Replaced fuel pump and filter, plugs and wires, both post 02 sensors, air filter and battery and no change. I've heard of MAF sensor and catalytics causing these problems, but anyone with similar problems please let me know as both are kind of expensive to repair and i'm gettin sick of throwin money away.

Yesterday i was driving my 99 gmc 5.3L Z71, and it made a huge air leaking sound, like i had air brakes. I stopped and it quit, i thought i blew a tire, but no flat, it did it one other time, but i can't find any leaks, or even know of anything that has enough pressure to make that sound. Checked everywhere underneath and no signs of leaks, fluid or air, no clean spots that blew air off, nothing. I have had a dramatic power loss over the past few months off the line. Can't even spin tires and it sputters. I had to floor it to get over a small bridge. Replaced fuel pump and filter, plugs and wires, both post 02 sensors, air filter and battery and no change. I've heard of MAF sensor and catalytics causing these problems, but anyone with similar problems please let me know as both are kind of expensive to repair and i'm gettin sick of throwin money away.

check for codes and post. autozone or checkers does it for free.