Well, I can't say I had no warning. In fact I was diving home a bit early so that the engine would would have a chance to cool before I pulled the plugs to look at them, and pulled the air cleaner to look at intake manifold fittings [vacuum lines]. If all of them seem good, it's time to crawl under and take a look at the modulator.

What I had observed was for a couple of days, the transmission upshifted much too fast [in top gear before 20 mph] unless I manually downshifted. At highway speeds [over 50] diving felt fairly normal.

About halfway home, the engine just stopped in rush hour traffic. I coasted to a stop on the left median [oops] next to the guard rail. No room to open the hood and tinker. Two hours and sixty dollars later, I was home in my driveway. Hopefully tonight I will finally get some time to tinker with it.