Agree cam cover gasket, needs replacing, they go hard and brittle with age from all the heat cycles they have to contend with. Oil finds its way at the exhaust side and drips onto the exhaust and gets burnt, tell tale sign is the smoke it produces. The centre plug well gaskets which provide the seal around the spark plug wells also start breaking up and leaking oil into the wells, look for oil in the wells when you remove the coil packs on each plug. Also be aware that under all the cover retaining bolts are rubber seals, these need replacing and come with some replacement gasket sets, they provide the seal between the cam cover and the bolts. Good advice on using gasket sealant around the half moon shapes at front and back of the cover and across the vanos joint. I use Blue Hylomar as the sealant, only need this around the front and back of the cover, the straight runs either side get sealed by the ribbed shape of the new gasket being compressed when tightened up. Very important that its all oil tight as if its leaking it will also allow air to get sucked in as well, when it has an air leak it will upset the fuel trims and cause bad running.
