1992 toyota pickup 4x4 v6 engine

I am really hoping you guys can help me out. I am new to posting but read up on many of threads. I just moved down from Alaska to California and have been trying to pass smog. I replaced the coil and o2 in hopes of passing but I failed the NO2 so I am now replacing the cat.

A couple of days after failing, I was driving when all of a sudden I lost all power. The engine bogs down now under load and when it bogs down I can hear a whistle or what almost sounds like a loose belt. I checked the belts but they're nice and snug. After beating my head against the wall all night all while reading the chiltons manual, I got a revelation. I believe its a vacuum leak? I am beginning to think that during the smog check they didn't replace a vacuum hose properly and it came loose. I just went out and visually inspected the vacuum hoses but can't see anything.

Here are the symptoms. When I first start the engine all is good, idles fine revs up fine. Then going around the block the sound appears and the engine will bog down and acceleration is difficult to say the least. It will also at times buck.

What do you guys think? Do you know which hose the smog techs would have messed with and am I on the right track? I did read similar problems with the bogging down under load but nobody has the added whistle or screeching sound. Please help! All advise is greatly appreciated.

 

Its hard to tell what a sound is over the internet. Anyway you could take a video of what it does so we could hear it?