Last night, I investigated the problem online. I discovered that it may be a vacuum line problem. I went outside and looked for the little tubes that come from the top of the engine and look what I found... A dry-rotted line that was split right open! Voila!
So I thought, how hard can it really be to change some tubes! I went to the auto repair shop of my choice and purchased 4 feet of line to change all three. If I'm going to change one, I better go ahead and change three. All of them looked rough! So, one at a time, I cut one off... and replaced it with a new one.
I had a hard time squeezing the new line on some of the fittings, so I used some Liquid wrench on them. Went right on!
The new vacuum lines were on and looked good! Shortly after, I went for a test ride and was amazed.
Not only were my face vents blowing harder than ever, the truck ran better! The idle was smoother and I believe I gained horsepower. Maybe it is my imagination, but I doubt it.
Here's my point. Don't run straight to the mechanic when something is wrong. Investigate it a bit, evaluate the work that needs to be done, and decide if you can tackle it yourself. It may save you some money.
If your vehicle is as old as mine (mine is a 97), you might want to go check the vacuum lines. It may fix some things!