The 93 Fleetwood started running a little rough earlier this week - idle became rough, not as much power as usual, etc. It was a regular throb that varied exactly with the speed of the engine. I figured I was missing a cylinder or something - definitely an ignition problem - it was too regular/consistent to be fuel delivery on a TBI car.
I have recently changed the distributor cap, rotor, and plug wires, so it was time to go after the plugs themselves. Had to wait a day for Advance Auto to order in AC Delco platinum plugs (OEM replacement), but at least they could do it (Autozone couldn't get them).
Was worried I couldn't get it done this weekend due to a big cold front and then the remnants of hurricane Ike, but Saturday turned out to be a great day, so I got under there and changed them all out.
Here are the old plugs - cylinders 7, 5, 3, 1 and top and 8 through 2 on bottom:
Looks like cylinder 8 was my problem. Car runs smooth now!
Next on the list is a coolant flush - it's looking a little dirty in the overflow reservoir.