I finally fixed it. It was so simple I'm embarrassed to tell you what it was. A vacuum line had a hole in the underside. The hole finally got big enough to hear the leak over the normal engine noise.

Smoke

 

Betcha I can guess where it was at. The line that goes from the PCV valve to the back of the engine. The elbow wears out and a hole develops. Happened to me just a few months ago. I finally found it the day before it was going into the shop. For anybody out there that has 70,000+ miles on your truck, you might as well replace it now, because it's going to be happening sometime soon if it hasn't already.

 

You are correct. It only cost me $5 and one knuckle to fix it.

Smoke

97 XLT, Flair Side, Trans-Go Shift Kit, Strait Pipes.