Hi, I'm new to this forum, have a 2005 Citroen C3 1.4 sx petrol auto, decided to clean the engine after having some oil leaks fixed recently. I bought an engine cleaner from Halfords and sprayed the engine with it following the instruction on the can, covering all the electrical parts. Then washed it off with a pressure washer. The next day the engine stalled a couple of times whilst idling. The next few days it didn't stall but the idling remained rough. Driving is ok, the engine management light doesn't come on, no loss of power, etc. A friend said it might be the lambda sensors around the catalytic converter are faulty. I just wonder if anyone had the same experience and more importantly what's causing the problem. Many thanks.