mbell wrote:I'd stick the timing light in the car go for a drive. If it happens again connect the timing light to see if the ignition system is working.
If it's fuel I'd consider temporarily fitting fuel pressure gauge so you can see if it's low fuel pressure/flow.
Having ran old unreliable cars throughout the 70's and 80's I built up faultfinding reflexes that still live with me today, at the very first missed beat I look immediately at the tacho, if the needle has dropped or is flickering then its an ignition fault, if it remains steady and falls in line with the dieing engine revs its likely fuel or these days a broken fan belt, with modern ECU's sensors and tachos the reflex doesnt really help but on an Elan its something that you should develop, the OP said the engine cut out, eve at idle there is enough time to see the tacho telling its tale.
I cannot recall the science but a 4 cylinder ignition system is most likely to have a heat related failure at aroung 2K RPM whether it be points or electronic ignition, its something to do with dwell angle and coil saturation, I was designing a programmable ignition system back then and did a lot of studying because electronics were new to me, now I have forgotten more than I learned! But I know the 2K thing to be true as later I worked for a company that made replacement ignition modules and also made the units for Lumenition (there is a big story there, thos of you that had them fail in the early 90's when the reliability was at an all time low thanks to this company would be enlightened!) they would try their hardest to refuse all warranty claims either saying the returned unit was not manufactured by them or putting it on the tester for 30 seconds running from tickover to max RPM, I would retest these "no fault found" units at 2000 rpm and after no more than 2 minutes they would fail exactly as the Customer had reported.