p0420 and p0430

[elvis1985]

hi all. I am having trouble with my 1999 mustang gt with the error codes of p0420 and p0430 (catalyst system below threshhold bank 1 and 2). The car has got no cats and has not had any for at least 7 years. i have owned the car for jus over a year and it has being like this for the last few months. I have noticed that there is a slight misfire at low revs about 1500 rpm. I have replaced coils, plugs , mil eliminators and nothing seem to have worked. I have just took a few recordings from the ive data on my predator tuner but not sure what figures to look at, really starting to annoy me now, please help.

Thanks mark from york in uk

[Vas@Diablosport]

The p0420 and p0430 codes can be disabled with a custom tune from a CMR dealer. CMR stands for "Chip master revolutions" and is our custom tuning software. To find a CMR tuner that can assist you, please select the "find a dealer" in the upper right corner of our website at www.diablosport.com


These codes are most likely not related to the misfire. Are you not getting any other trouble codes?

[elvis1985]

there are no other codes that come up on the car, just the catalyst codes

[Vas@Diablosport]

If you aren't seeing any other codes, then you have 2 unrelated situations. To get rid of those codes, have someone create a custom tune for you as described in my previous post.