My car's been burning a bit of oil lately. Smelt a bit of a burning smell last night, like metal friction, oil was pretty low so I topped it up. Started it up this morning, seemed ok then I stalled it whilst I was looking for the garage buzzer. Then when starting up again it runs really rough, like not all cylinders firing or it's missing but i have had the leads done recently but not sure about the plugs. Any diagnosis? The whole car chuggs/vibrates from the engine. I was told my engine mounts were worn, maybe they've given up?