well I maybe your saviour but the news is not good I am afraid. The fault to me sounds like the camshaft dephaser pulley is failing and the symptoms of it failing are the rattle like noise on start up, plus the uneven idling, stalling etc. I am surprised it has not been diagnosed sooner by one of the mechanics you have been to. Its a very common fault on the 1.6 16v
K4M engine. The dephaser pulley operates the variable valve timing and its a mechanical pulley electronically controlled by the cars
. To fix the fault you will have to have the dephaser pulley replaced for a new modified pulley plus also as the timing belt goes round the pulley and has to be removed to change the pulley it is strongly recommended that the timing belt is changed as well, along with the other pulleys, tensioners and the water pump and coolant. Its also worth having the
housing cleaned out as well as this can gum up. The cost of putting the car right at a Renault dealer you are looking around the £700 mark but a decent independent Renault Specialist should be able to do the same job much cheaper. What I would do though is give
Renault Customer Services
a ring, mention about the rattle like noise on start up and you suspect the dephaser pulley is on its way out. They may well pay for or contribute towards the repair costs, although you will have to pay for the water pump and to have the
housing cleaned. Just don't mention you have known about it for 2 years, make out its only started happening. Let me know how you get on.