Problem question

Hello I have a problem with my Seat Cordoba Vario 1.6i… 3 weeks ago he was in the Werstatt….because he only ran on 3 cylinders and came out of the exhaust blue smoke….the tap sensor was replaced..and the idle control was cleaned…there the problem was then 3 weeks away…. now I have the same problem again when he has his temperature he runs on 3 cylinders and again bluish smoke…the second cylinder is wet….thereupon the injection wasvent il ….Distributor cap and runners and spark plugs and ignition cables changed….but the problem is still there…..maybe one of you still has a tip for me on what else it might be. LG Angel