I recently had a burnt valve on a 2.5l 10V. All the work has been done to correct this. Initially everything seemed fine. Now a week later I'm getting sluggish performance. There has been a concern over the exhaust. When a hand is placed over the exhaust pipe oil is deposited onto my hand. Does this suggest a piston ring problem although oil wasn't deposited on my hand prior to the work or could it be faulty valve seals? I have used more oil than I would expect in just one week's driving although there was previously an issue with the rocker head seal. This was also fixed during the major repair work to the valves and head. Many thanks Tony