Thanks for the response Klaus.

Yesterday morning, I inspected the first three plugs on the passenger side of the engine. They all appeared to be in the same condition. Just a light tan color with no buildup of any kind. They were new about 10,000 miles ago.

Now, the cap and rotor haven't been replaced in a lonnnnnggggg time. With everything running just fine, and the mileage normal, I didn't consider it.

I pulled the cover to check out the vacuum tree, and traced a line to the pressure regulator under the fuel rail. It looked cracked right where the rubber line bends. I wiggled it and it literally fell apart. I ran a new vacuum line from the tree to the regulator. I started the engine and crossed my fingers.

It seemed to start a little quicker, and idle more normally. I'll monitor things for the next couple days, but it seems the vacuum line to the fuel pressure regulator was the issue.

Thanks for helping out again Klaus.