I have a 2006 Pathfinder SE and I'm getting a p0300 code which can be a lot of things. I'm also getting very loud "engine" noise under the drivers floorboard only during heavy acceleration. It doesn't happen under mild acceleration on a flat surface. Also It's not an open exhaust noise. I'm thinking it is probably a clogged left front CAT. Anyone else ever have this problem or can confirm this?
By the way, the plugs and coil packs are new but I wouldn't that would cause the noise