"#1 - was hoping for a way that didn't involve flammables.
Edit - the noise is loud, high pitched and sustained."
Sounds like a vacuum leak, all right. If it is that loud and high pitched, you should be able to locate it by feeling with your fingers and then covering it.
"#3 - I tried the 7/8th - didn't work, too small."
Time to invest in some tools.
The 7/8 inch works well for the O2 sensor.
Incidentally, you could also have a 02 sensor going bad if it is hesitating at high speeds, but you should get a CEL code for that.
