1997 Cobra. On the way home from work one day, I ran out of gas. Was between paychecks. I put cheap gas in. They next day, car had a bad knock. I immediately parked it, assuming it was something like a ring knock. But after reading quite a bit, could it just be cheap gas? I recently bought the car, it sat for years. Had to put it in shop to get it running. They flushed fuel tank, new pump, filter. Oil, filter, spark plugs. Now this... I cleaned imrc's. Drained oil, no metal. Checked under valve covers. Nothing unusual. About to work on pulling oil pan and check the rings. But a little complicated in my current situation. Few tools. No place to work on it. Very little money due to coronavirus bs..