I highly doubt it is an oil comsumption problem. The engine has only 45000 miles on it and does not consume oil. The level on the dipstick does not drop at all during the 3 month interval between oil changes. My 78 Ford uses about 1/2 quart every three months and that has no effect on that engine at all. I've heard about these engines getting manifold leaks and using coolant, but the coolant level hasn't dropped below the full cold mark in the 2 years I've had this car. The deposits on the plug were definately not oil deposits, I've seen my fair share of oil fouled plugs. Further more, I can't imagine how minimal oil comsuption can cause a rough idle that turns into a full miss at speed.
At this point I'm really beginning to suspect a bad coil. I've swapped the 4-1 coil with the 5-2 coil, to see if the fouling moves with the coil. When I drove the car after swapping the two coils it did seem as though the vibration at speed had changed(I might just be nuts). I'll see what autozone has to say about the ignition module and coils this upcoming weekend. Hopefully my hunch is right, but it usually isn't
