Been there and done that. I wish I would have checked the UIM first. I was probably even told that the same way you just were, but i didn't know my a** from a hole in the ground at that time. Didn't even know what half the parts were! Grabbed a Haynes manual and this site, and gave it all i had. So yea before you do anything else, take off that plenum, and stick your finger in that hole. When i did that, little balls of chewed up plastic were just rolling up and falling out.
1995 Bonneville SE