I recently replaced the valve stem oil seals on my car and have noticed of late that if I accelerate hard, foot to the floor from a standing start I get a cloud of blue smoke although this does not appear to happen when accelerating after a long period of overrun or idle which is what I believe is classic sign of valve guide wear. Also recently having been sat in traffic for 40 minutes I noticed that the engine started to misfire although it didn't get particularly hot and remedied itself once on the move again. I have my suspicions about the head gasket although there is no loss of coolant or oil and water mixing.
Could anyone shed some light please?

Many thanks!