Does anyone know how having a SES coded P0420 (cats opperating below efficency) effect how your engine will run, more importantly the A/F mixture.? Do people just run there car with theses CEL and have no problem?

 

probably wont affect anything except gas milage, but yes it will affect your A/F.

 

Do you by chance now how much of a difference it make on your A/F ratio? Enough to run lean or rich?

 

I can't say how much for say as in if it will change your ratio, biggest difference is going to be the 2-3 mpg you start losing. If it leans your car out which is possible, listen of detonation ping up in the higher RPMS. Over and above you should be fine untill you replace, but dont take that to the bank. Replace as soon as you can, dont hold off because you think "it wont do much" One thing leads to another untill you have a domino affect of **** piles dropping on your car.

 

So do people just drive around with the CEL and not have any problems? I have a code P0420 and tried everything and cannot get it to go away.

 

Bump for a ray of hope?

 

You will not pass emissions testing in most states with a CEL. You could get an Osiris reflash to eliminate the CEL. Or just buy the less expensive Cipher and clear the code as needed. Or get aftermarket cats. Or pick up stock used cats for cheap in the marketplace. Lots of options!

 

I have after market cats and tried the anti-fouler trick and checked for leaks, ect. and still cannot get that code to go away

 

Has anyone solved the CEL for HFC on 2004.5 and Later 350Z's? I tried the anti-foulers and still didn't work. Please any ideas?

 

Why do you have an aftermarket cat? are you racing sir ? (officer hardass)

 

What?

 

I have the same problem and I was told it could be the o2 sensors i changed all four of them and still the light is on. Also my rpms are not stable when you put it in neutral from 6th gear, almost like its about to stall for few seconds and then the needle jumps back to normal, but sometimes it stalls if was pushed hard in 6th gear and then put in neutral.

 

I have that same problem!!! no CEL. Dealer told me one of my o2 sensors is bad recently, but I think it is unrelated.

I've had this problem for 3 years now!