killer924007

I just bought my 2000 maxima SE(california spec) 1 month ago.First!!! the check engine light bulb dead and i install a new bulb and the check engine light is on,and i took my car to auto zone ..got the code P0420&P0430.damn! it's the catalyst codes.And then i saw TSB that the ECM update may work for my 2000(cali spe),and then i took it to dealer to update the CPU.it cost $160 cus my car is out of warranty since it is over 80000 miles.And they said the 2 pre-cat are no good and want me to get a new one.It cost like a $1000 buckss for 2 precat..Ohh my god!!! that's crazy.and i told them i just wanna do a ECM update first and see it may work since i got a TSB paper with me.OK!!! now after 25 miles driving..the light is on again!!!!! ohh man!!!!i am very dissapointed to throw that $160 for that !!!!!!!!
Can someone give me a suggestion for getting a Y-pipe from wrapspeed that may work to slove the error codes problem? My california spec need a y-pipe to take over the 2-precat right??? and the sounds loud for that Y-pipe..cus i don't wanna throw $1000 dollars to buy the original cat from nissan..Help plz!!!!