whistling sound when gas pedal pressed after adjusting the throttle body?

u may have possibly knocked off a vacume line on accident and not noticed something to check anyway

For one you should have never adjusted the throttle body. There is no reason to do this unless it had already been moved from it's factory setting. It needs to be returned to it's original position according to the procedure for setting the minimum air rate. If it was having idle issues and this helped then you have an IAC problem. The whistle you hear is air being drawn acrossed the partially open throttle blade at an accelerated rate. Before the IAC would be further open opposed to know closed completely and some of the air flow would have been directed through the IAC passage.

First make sure you didn't leave a vacuum hose off, then make sure you didn't crack a vacuum hose while moving them. Next check would be if the gasket between the manifold and throttle body is good. You might not have torqued to down enough, you might have misaligned it, it might have cracked and allowing air to enter there.

Uhh, i would first assume a leak, or a something blocking the area gases are passing through, but of course you haven't specified what 'it' is so i can't really help

Sounds like you pulled off a vacuum pipe somewhere.