Tickover - gone, then fixed itself

More fine weather, warm too - so took the Zero into work;

The M25 was horrible this evening, 30+ minute crawling along, then the odd thing & reason for this post; I lost tickover - the car was running fine just stopped when I took my foot of the gas.

I stuck with it back to Maidstone, and once in town tickover was  back - must have fixed itself...

                                     SAM
                         I mean it fixed itself.

                                     SPOOR
                         Fixed itself.

                                     DOWSER
                         ... ixed itself.

                                     SPOOR
                         Machines don't fix themselves.

                                     DOWSER
                         ... fix themselves.

                                     SPOOR
                         He's tampered with it, Dowser.

(c) BRAZIL  (Terry Gilliam, Tom Stoppard & Charles McKeown)

hmmm...

I don't think it was fuel - that should have made running lumpy, nothing got particularly hot, perhaps a bad connection to the IACV?

The headlights were on, and volts a little low, I guess due to the load + tickover - possibly lose alternator belt?

Something to mull over

Update 26/9/13 - I caused the same effect today, clear run 80+ miles round trip, then sitting in traffic had the main beam lights on - switched on the heater fan, volts dropped to 12.2v and tick-over went lumpy.

Update 17/2/14 - Has not re-occured, tick over is rock solid. Battery has been fully charged (if it was that), IACV 12v feed now taken from a different source (if it was that). nothing conclusive.