I got a '99 bmw 740il that is leaking and burning oil. It shoots smoke out the exhaust when i first start it from burning oil. And the car misfires when idling, i did a tune up and the spark plugs were soaked in oil causing the tune up not to help anything for long cause it was missfiring the next day. Does this sound like the valve stem seals? I bought new valve cover gaskets and grommets and im gonna replace those this weekend, im hoping that will help. Comments please
The symptom of bad valve stem seals is blue smoke after sitting overnight. But once that smoke is gone, a bad valve stem seal won't have any effect on engine running or idling. And it certainly won't cause a misfire. Worn valve guides can do all those things. You have far more serious problems than just valve stem seals. Get a wet/dry compression test and a cylinder leakdown test to isolate the problem to either valves or rings.
