1994 Renault Laguna RT Sports review from UK and Ireland

I have owned this car for almost 4 years. Two years ago I had a slight bang with another car. Since this time the car started to misfire. The local Renault dealer could not identify the reason only that it was misfiring. To date this year, I have spent £800 on the car for repairs and still it is breaking down. New starter motor, new TDC sensor and plugs and leads. New starter motor again, New coil and propose new Ignition Module perhaps now a new computer. To date it has broken down 7 times for me. This time however, the garage say it will cost another £600 to repair for a new computer. Surely, the garage could identify the exact cause as I am paying for what they think it may be as apposed to what it wrong with the car. Does or has anyone else had similar problems with their Laguna either cutting out/stalling etc. My car still will not start and the garage are clueless as to what the cause is. I would be very grateful for comments?

I love my Laguna to drive and for my family. I only wish these things were not so complicated to sort out.