Well, I said I'd report back....
The cheap 'n cheerful coils work as well as the originals (grey tops, by the way, on both sets), but didn't solve the problem....
Nor did a set of plugs.
Nor did a new crank position sensor.
Nor a temperature sensor.
Nor the lambda sensor
Nor cleaning and testing the MAF.
Nor a new air filter.
The main stealer said 'There's nothing wrong with it". Nice of them to record the symptoms and 'No fault found' on their invoice though. That may be useful later.
It has the local independant Renault specialist baffled. There's no errors in the ECU (well, there were some concerning the airbags, but not exactly related). They suggest replacing the cat. next, although that may be desperation setting in.
Anyone else have any ideas?
It is a 2005 Kangoo 1.6 16V Automatic.
Poor starting.
Very low idle speed / stalling when cold.
Poor pickup from idle, even when up to temperature.
Cutting out completely above about half throttle.
Any sudden movement of the throttle causes an audible blowback into the inlet manifold, or cutting out completely until the throttle is closed again.
I would say that has all the classic symptoms of an over-lean mixture. If it had an SU carburettor, I would be winding the main jet down a couple of turns, or try driving with the choke on to see if it improves.
Getting up hills or around roundabouts is quite an adventure at the moment. It took about 5 miles of the M4 to accelerate up to 70 after a stop at Leigh de la mare services yesterday evening, and utterly refused to climb the gentle (by local standards) hill from Pontypridd to Graig.
Then, just to add to my woes, shortly after finally reaching 70MPH on the M4 on the return trip, I met a pigeon coming the other way - Time for a new windscreen now as well!