2003 Nissan Sentra SE-R Spec V 2.5L QR25DE
I have a 2003 Nissan Sentra SE-R Spec V. I currently have been having these issues and wanted to here if y'all had any ideas. Okay so I had only the code P0420 the check engine light disappeared for a bit then randomly came back on but this time with code P0302 I originally fixed code P0302 with new spark plugs and now it's back for the code P0420 I just had my car at the dealership shop which they changes both O2 sensors so it's not that also for some information a few days ago I quite literally had everything after the precat fall off my car when driving so I only have the exhaust manifold and precat both O2 sensors are there. My question 1st question is for the P0420 should I just dump out the cat until I can get an aftermarket exhaust manifold or is there something I should try before that? My 2nd question is after I check the spark plugs if there still good should I chang the coil pack and spark plugs boots and go from there?