I have a bad misfire on the 3rd cylinder in a 96 Saturn Sl2. Changed coil pack, spark plugs, wires. Oil was changed right before it started misfiring and I haven't driven it since. I'll start it up occasionally and I recently checked the oil and its purely black. I'm thinking it is blowing by the piston rings when it combusts. It runs rough and blows bluish white smoke out of the exhaust, smells like unburnt fuel not burnt oil. Either it's the fuel injector or rings. I need some input, Thanks.
sounds like you have lost compression in that cylinder from blow-by past the rings. One thing you could do is loosen the oil cap off when its running and if exhaust comes out of the oil cap area, the engine has blow-by. thats what turns your oil really black quick. if it is blow-by, try using Lucas Heavy Duty Oil Stabilizier. Its great for blow-by, to a certain point i mean. Also try switching a coil pack around with another cylinder just to make sure its not a bad new coil pack. other than that its a complete engine rebuild for the rings.