Funny Exhaust Noise

Yesterday, at the highway, I was drivig at 200kmh for 3minutes.

Engine was ok to give gas etc etc.

The thing is, I took the little hose thas sits on the air box(since i had the pd160 intake for like 3 days) to see if it would go better.

Now, when i got home, it sounded a little strange.

I though it was the muffler and so today, I started my car and drove for like 2km.

Mean time, the car was threatning to stall, wille i was trying to give a steady trhotle with an irregular idle at the beguinning.

Got my car home, lifted with my standard lifter to see if it has any leak at the mufler.... couldnt find anything, but couldt also see the colector as it was not enough lifted and i was afraid (one ton on top of me kills me for sure).

I did put the hose back on, but i still hear that funny noise.

What can it be?

If it was the colector i would be able to notice it right aways, since my car is a little smoky, right?

Help please.

Thanks and i am sorry about spelling......