I’ve spent some time trying to work out what this problem is and I can’t spot it so I’m hoping a consensus can be reached here.

The car cuts out in hot weather (over 25 degrees C) and it seems to be more of a problem when barely moving in slow traffic. It gives a few seconds notice of rough running then stops. Last time it did it I noticed that the volts had dropped below 10v at the same time. It sometimes restarts straight away, and if given ten minutes rest it’ll be ok for a while. I’ve got around this by keeping the revs up and being aware of situations where this isn’t happen. The radiator fan is set to come on reasonably early and I’ve fitted an over-ride switch for the fan to turn it on earlier in case of traffic jams but I’m not sure that is the issue. The fuel vaporising in the pipes was also suggested but giving it ten minutes rest wouldn’t be sufficient to cool the fuel.

My suspicion is that it is electrical, and that when moving slowly build up of heat in the engine bay is causing some component an issue. The question is what ?

It’s a 4.6 RV8 with an Omex ECU. The injectors have been replaced recently as have the rubber fuel pipes with no resolution.