Last month my check engine light came on and I had it scanned. The code came up as 430 and 420. Now my car has a light exhaust smell in it while I'm driving. It also has a funny smell in it when I get into it after its not driven for a couple hours. Do you thing this smell is caused by the cat. I had the exhaust system checked and it didn't have any leaks. I am looking at get the bank 1 and bank 2 cat by Walker from rockauto.com. Any advice on this matter is greatly appreciated.

 

this is a trick i found in youtube. Add a gallon of Lacquer Thinner with a half tank and bingo it cleans itself

http://www.youtube.com/watch?v=5icTmYItwiE

 

The precats on Nissan's, especially Maximas, Z's, G's break down and turn sideways, blocking exhaust flow and sometimes damaging the engine. I would highly recommend you either replace them or "gut" them completely and install non-foulers

 

+1 to gutting them. They're probably clogged and will soon fail you. Mine clogged up on the highway and I had to limp my way home. I'd recommend not gassing the engine too hard in the mean time or you might blow something. Personally I installed an o2 simulator and it was really simple.

www.o2simulator.com