So a couple days ago my car would not idle and i had to give it gas to keep it alive and some times it wont start without gassing it. ANd smoke and metal shards were coming from exhaust. I recently put hfc on the car and the filter to catch the cube one shot out the back of the pipes.

So i took it to Nissan to run the codes they said i had 3 Multiple engine misfires ,low engine oil, and another.


Any Ideas maybe 02 sensor

 

perhaps your High Flow Cats are failing... there has been documented issues with that happening a while ago... esentially the honeycomb inside the HFCs would just melt..... Put your stock cats back on and test again.