Update:

The "bad" tire was worn down to the belt cords in one spot, so I took it to a tire dealer yesterday and got a cheapo used tire put on to make it safer until I diagnose/fix the underlying prob. and get all new tires.

While it was at the tire dealer, a Goodyear tire center with a good local reputation, they were nice enough to have their alignment/suspension mechanic look it over for me, in detail, and for free.

Findings:
He kept pressing me, questioning me whether the bad tire had ever been on the back of the car. It had not. He kept asking because, in addition to the outer edge wear mentioned above, it had at least one big diagonal swath of wear clear across the tread. He said this is typically found on rear tires and is an indication of wheel tramp (up and down) due to bad shocks in the back. Not usually found in the front.

Joints/wheel bearings:
He also noted that the right tie rod end was beginning to show a very little looseness. Note that it was the LEFT front tire with the wear problem. All other rod ends, ball joints and wheel bearings were fine, good and tight. Left ball joint boot beginning to crack/split.

Bushings:
The sway bar bushings are completely shot, and I must assume that if they are shot, so are all the others under there.

Struts:
And, finally, the right shock strut is leaking, and he says they both look like the original ones (i.e. 16 years old, and over 250,000 miles).

My Analysis:
The right strut is leaking because it still has some strut juice in it to leak. The left one, where the problem is, is probably bone dry inside having leaked out ages ago. All the bushings are shot. But, thank heaven, all the joints have survived so far (I probablly will replace the one that is beginning to go loose). In that light, the problem really does seem to fit the diagnosis of severe wheel tramp due to completely shot struts, aggravated by completely shot bushings.

Now, if any of you have any suggestions of where to get good, high quality front struts for this car (1991 740 Turbo Wagon) at a reasonable price, I'd love to hear from you. Also, can the struts be rebuilt? The ones on my RX-7 can. This would save some $$$.

Thanks.
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Scott Cook - 1991 745T, 1985 RX-7 GSL-SE, 1986 Toyota Tercel (Don't laugh, it is reliable, faithful AND gets 41 mpg!)