I think you miss the point which several of us are trying to make; in short, leave the EGR valve alone. Change the spark plugs. It sounds as though they are fouled with partially burnt oil which is going into the combustion chamber pass the piston rings and the valve stem seals. These areas will pass oil on any high mileage engine. It’s expected. So, change the spark plugs, and (maybe, the distributor cap and rotor; and, maybe, the spark plug wires) to get the engine to be all it can be (burn its fuel most efficiently).
The distributor cap and the spark plug wires were changed earlier this year, so they should be OK.
You could be right about oil fouling the spark plugs. However, other things have happened that make me wonder if it is just that.
My car was hard to start this morning, the “check engine” light came on immediately instead of after the engine was warm, and the idle speed was 1200 instead of 900. When I got to work I turned off the engine, turned it back on, and everything was fine. Everything was fine going home too, warning light came on at the right time, rpm 900 etc…then I stopped at the grocery store. When I got back, I had to repeatedly crank the engine to get it to start, and the idle speed was up again. When I got back home I stopped the car, waited a few seconds, and started it right up, no problems.
If this was a fouled spark plug I would think that I wouldn’t see this kind of erratic behavior, especially with the idle speed. And now that I’m having periodic trouble getting the car started I’m more reluctant to try and fix it myself…especially since I don’t have the tools or really even a driveway/garage to park it in. If it was just a warning light I’d be more willing to give it a try…