First the moral of the story, then the story: replace your CPS (crankshaft position sensor) before it dies - or at least carry a working spare!
Yesterday evening, on my way home from my office, rush hour traffic, busy intersection on a main thoroughfare, and as I pull up to stop at a signal light the old girl dies on me. Crank, crank, crank, no start - and no blip on the tachometer. An under-hood inspection did not reveal any damaged wires or loose connections, so I needed to replace the CPS. I set about preparing to do just that and in short order a couple of nice local constables arrived on scene, having been notified of the traffic snarl I was causing. After I told them I had a spare part with me and the necessary tools they suggested the car be pushed to a parking lot that was probably 100 yards distant. While one officer directed traffic the other rolled up his sleeves and while I piloted he pushed me through the intersection. Fortunately there was a downhill slope leading to the parking lot so off I went. Long story short, I swapped in the used CPS I carried with me. This was the CPS - probably original to the car - that I took off and replaced with new when I replaced the head gasket, valve stem seals, hoses, etc. at 95k miles - 93k miles and 17 years ago. The car fired up, loose ends were buttoned up, and I continued my journey home where a nice cold cocktail awaited me. Whilst slaking my thirst and licking my wounds (hard to do at the same time!) I jumped on the InterWeb and ordered a new CPS. When it arrives I will install it - to make sure it is good, and for the sake of reliability - and relegate the used CPS to backup duty. Meanwhile, I am running on the old CPS, which at least allowed me to make it to my office this morning.
Interestingly, in hindsight, there was a warning sign that the CPS was dying. Yesterday morning as I drove to my office there were a couple of instances when I pulled to a stop and the idle dipped to 500 rpm for a couple of seconds, then recovered to normal (~650 rpm). I have not heard of a CPS causing this symptom - the usual is a failure to start - but I’m convinced now that the CPS was the cause.
So, in conclusion, I have once again found my boyhood Boy Scout leader was correct: Be Prepared!