Mike,
I just came back from the mechanic who put in the valve stem seals in October 1500 miles ago. He pulled the plugs to check for fouling. He said the #8 plug was fouled due to what he thinks is a bad transmission modulator that is not working. He said the trans fluid was being sucked up and fouling this plug. He also said to use a quart of oil in 1500 miles is reasonable. If after the repair I am to watch for consumption and plug fouling. If it still happens he's telling me I probably need the heads rebuilt at a cost of $5000 ( I won't do it , I'll sell the car at that point). I'm getting a little disgusted and the money barrel is starting to dry up.
Larry
'86 560 Sl