Your point is well taken, Steve. I guess, in my frustration with the situation, I'm looking for a shortcut. What makes it all the more frustrating is that my 560 SEC with 50% more miles and virtually the same drivetrain, has run flawlessly since the day I bought it.
It appears that also I'm dealing with the previous owner's lack of competent maintenance. Thanks for your reply.
1986 560SEC: 150,000 miles, runs great, but I've got to sell it (too many cars for one man)
1987 560SL: 122,000 miles, used to run poorly, now (thanks to forum), runs great!
1997 GMC Jimmy: Turned out to be a turkey.
1989 T-Bird Super Coupe: 150,000 miles, still runs great. Ford got it right.