Hi, my R reg Astra is not starting, at first I thought it was a missfire issue as at first the engine was running rough whilst shaking with loss of power. So I changed the spark plugs (no joy) I then changed ignition leads and replaced the coil pack (still no joy). I have now noticed oil on the spark end of the spark plugs ???
could be worn valves, piston rings, head gasket. you need to get the cylinder compressions checked before you spend any more money. a good garage will advise you.