My G35 randomly stopped at a red light. I was able to turn it back on. Sounded like it was having a harder time than usual but it turned on. I I drove it back home and ran a diagnostic and got p0335 and p0420 codes. We had a heavy snow week prior and I remember starting my car after the snow melting and my exhaust sounding different, almost like a deeper sound and i remember for a moment i could feel it in the seat. Drove fine for about a week then randomly shut off at a light, the day before I was able to drive it about 60 mi with no issue. I changed the camshaft position sensors and crankshaft position sensor. Last year they're about 10 to 11 months old not even a year, but since that issue I would get random shakes while in idol. So before I go out and spend money on new cats and a O2 sensors, I was wondering if anyone else has experienced a similar issue?