Hello guys, my Passat Bj 90 runs all at once only on three cylinders. I requested ADAC and he found that it was the valves. How can I understand that. Valves and ignition, what do the two things have to do with each other. The whole thing happened to me in Holland and I immediately went to a workshop and had all spark plugs changed. After that the problem was not gone. Then I immediately drove home (approx. 250km) and then heard after approx. 100km loud noise from the engine compartment, but only if I rolled slowly in the traffic jam. What happened there and how can I solve the problem or is everything already too late??? P.S. After another 100 km, however, the clapping stopped and I had the feeling of the car driving back to normal.