What can cause a loud whistle noise between the UIM & firewall??
 

Hi there I just finished re-installing my injectors and after I put everything back together, it took about a minute of cranking for her to start. And when I first give it gas, it made this loud whistle (sounds like those NBA referee's whistle) coming from between the UIM and the firewall. The noise seems to be slowly fading away now but I just wanted to find out what can cause this weird noise. Some things worth mentioning:

1. Car sat for about a month
2. Cleaned injectors, replaced all insulators & o-rings.
3. Replaced PCV valve (solve the gas odor problem)
4. Noise only comes on for about a second and it only happens when i first push the throttle.

Any ideas? Any help will be appreciated.

im just guessing but if you took off any vacume hoses and left them off that might happen. just guessing.

yes i did take off a bunch of vaccum hoses (like 5) but I'm pretty sure that I hooked them all back up. Funny thing is that I get perfect boost pattern during the test drive. The only thing "weird" was the noise.

not sure what kind of whistle sound
but the turbos will do it if u install a down pipe
also if the alternator is going bad it makes whining sounds that are affected by rpm increases