It sounds like you're in the right area, but the spray will dissperse and be sucked in by a leak that may not be right where you are spraying. That's why I suggested removing the throttle body. On a skill level of 1-5 it's about a 1. Then If you look at things carefully as you take it off, chances are you will find the leak. Another method I found that is effective in finding vacuum leaks, once you've found the general area as you have, is to coat it with Spray lubriplate grease with the engine off. Then as you watch, have someone start the engine and look for where the lubriplate gets sucked in.