I did some more tests...I disconnected the pax side coil wire and the engine idled inconsistently, just as it does when that coil is hooked up, (except on 4 cylinders.) I reconnected that coil.
I disconnected the driver's side coil and the engine idled quite evenly (though clearly on 4 cylinders).
Going further, I reconnected the coil and unplugged one spark plug wire at a time from the driver's distributor. When I disconnected the plug nearest the driver (is that #1?), the engine idled evenly, though clearly not on 8 cylinders...no jumping. Reconnecting that one, and back to jumpy idle.
This tells me (correct me if you have other ideas) that I have a bad (in order of suspicion):
1) distributor cap
2) plug wire
3) spark plug
The plugs are Bosch Platinum. The wires and dist are Autozone...(Duralast?) and all were replaced 20,000 miles ago.
If I had the energy right now to disconnect and reconnect the intake stuff, I'd go switch the plug wire with the another one as long to see if the problem follows the wire, but I don't so I'm not going to try that today.
I'd really like to get the shield off that's at the bottom half of the distributor cap, but I can only locate 2 or 3 of the necessary bolts. Is there a picture to help locate the bolts that aren't really visible?
Joe