Megane 1.6 petrol, 5 years old, 38000 miles.
After five to ten minutes on the first trip of the day, it dies. It's happened twice while moving, twice idling, and several times after stopping and trying to restart. Once it just faltered badly while moving at 30mph, and was reluctant to restart after a short stop about fifteen minutes later, but did.
It takes from seven to fifteen minutes to recover, after which it starts OK and carries on for the rest of the day, stopping and restarting as necessary, as if nothing had happened. No engine management warnings at any time. The coil is a group of four, and I've taken it off and cleaned its earth connection. Four separate injectors. When it's in not-starting mode it has the sound of not being anywhere close to starting. No response at all, it's not just one or two cylinders down or the mixture not being quite right.
This has the feel of a vapour lock problem, particularly in the time delay, after which it always restarts and continues. It's getting worse, but this may have something to do with the weather. If we ever get a cool day again and it improves, this would be further evidence. It started soon after an exhaust replacement, but that coincided with the weather warming up. The heatshields seem to be all in place and the fuel lines don't go very close to the exhaust. No problems in the hot weather last summer.
I've changed the fuel filter with no improvement. I did this about ten minutes after shutting off the engine, and there was no fuel pressure there when I opened the connection. After the dire warnings in the manual, I wonder if this is normal. I'd guess the fuel pump is the next candidate, unless anyone has other ideas.
I'd be happy to pay someone competent to fix this, but I have no interest in donating £500-£1000 to my local Renault dealer's next showroom refurbishment and still have problems afterwards. Google has helped me find lots of people with similar problems, but as usual, without any answers. The immobiliser seems implicated in some people's problems, but I don't think it is here. No lights and this fixed delay before things work again seem to make it unlikely.