Hi, I bought Ford Mondeo mk3 with 1.8l duratec he engine. And I have noticed that car has been throwing blue smoke when accelerating from coasting (deceleration). I know that it's burning oil and it may be a stuck pcv valve, bad valve stem seals or bad piston rings. If the valve stem seals were bad, the blue smoke would come after cold start and eventually disappear, but no smoke at all comes on cold start. no smoke when idling or driving normally. As I said it only comes when accelerating after going down the hill and when I push the pedal to the metal. I don't believe it could be a bad piston rings because the engine sounds smooth and there is no loss of power. yesterday I took out the intake manifold and there was pool of oil inside and a pcv valve was stuck closed. I've cleaned up the pcv valve, but I haven't cleaned the intake manifold (there's still some oil inside). I put everything back and took a ride to see if the pcv fix really helped, but it doesn't. Maybe it still sucks in oil from the intake manifold? because I haven't cleaned that up. Or maybe there could be other problem?