Okay, so I have a fedspec 2000 SE MT- no intake mods other than a 1 year old 2K1MAF. This code first appeared after installing cattman exhaust from headers to muffler last summer. Since then it has come on and off about 4-5 times with what appears to be no ascertainable trigger.

After its first appearance, I retightended all the bolts from header bolts to the muffler at which point I cleared the code and did not appear until ~500 miles/tank and a half of gas later. I rechecked all connections for the intake and decided to not clear the code. It SES remained for about 200 miles and then turned off for about 100 miles at which point it came on with the p0420 again.

This has been going on now since last summer. I have not had it dyno'ed since aftler install of the exhaust and VAFC but my impression is there has been no change in performace - i did lose some mpg as expected from these mods (~20 miles less at 3/4 tank keeping my shifts between 2,000-2,500 rmp).

I plan to look replace the plugs and check out the injectors when it warms up.

Any thoughts would be appreciated.

 

P0420 codes usually means an ECU reflash by the dealer.

P0430 usually means main precat

I had the latter code on a 2000 max and was told by the dealer that if I had the p0420, they could try the reflash and change a few paramters but since i had the p0430, they were almost certain that it was the main precat, and it was just that.

BTW, there are a ton of info on this code here on the forum.

 

thanks nsnrider - but i did do my search and am going by the most recent thread http://forums.maxima.org/5th-generat...t-do-i-do.html

 

reflash is not applicable to fed spec vehicles.

you need de-foulers, basically extensions for your o2s so your rear o2 reads "slightly" less exhaust gas vs the front o2.

 

nismo_star - i've considered doing the nonfouler to the post cat o2 but i am concerned it will give a higher AFR reading.

Do you know which o2 sensor(s) the ecu of a Fedspec uses to adjust a/f or if i can use my vafc to mitigate this "mechanical sim"?

 

Front O2s participate in control of A/F, i.e. the ones before the main cat...

 

Fellas, I don't know for sure but I don't think there should be two much difference between our cars. I just got the P0420 on my car too:

P0420 - Catalyst System Efficiency Below Threshold (Bank 1)
P0430 - Catalyst System Efficiency Below Threshold (Bank 2)

http://forums.maxima.org/6th-generat...rade-time.html