My 03 doblo which does not run smoothly on cold mornings was finally diagnosed with a rotor position sensor problem. The mechanic said it would cost so much to fix in the factory that I might as well get another car. He put diesel treatment into the fuel tank to help the car run smoother. It does, slightly, and given our recent freezing weather, the problem has not worsened. It's just annoying to have to spend about 20 minutes to warm the engine up before it can function properly and be fit enough to go on main roads. :bang: Any suggestions?