Well i have a problem with my car the code is PO420.I have been told that i need a new Manifold with Ultra low emissions one that has a Convertor in the manifold and i have been told that is crazy.Can anyone help me out that might have had a problem with that code I have already had the Cat Convertor replaced.

 

Have you done anything to your exhaust system recently?

P0420 means that the o2 sensor after the catalytic converter is not getting a lower reading from the o2 sensor before the cat. If you have no modifications to the exhaust system then you cat is dead.

There is many different ways to approach this problem. Does your state require emissions testing?

Ultimately you should replace the cat which sometimes can run in the hundred dollar range. There is a temp fix that can hold you over for a little while if money is an issue, but I suggest changing the cat. There is a chance that the downstream o2 is bad, but not likely.

k3v

 

Well i just had the cat replaced like 4 months ago or so but its a universal one i heard that neons sometimes have problems with them but I have heard about the o2 sensors too so im thinkin about replacing them and seeing if that fixes it.Thanks for your help should i replace just the downstream o2 sensor or both??

 

p.s Yes my state requires Emissions testing and my check engine light has to be off.

 

i am running the o2 sensor trick method, so im almost positive my cat is dead. i also had it recently replaced (about 6 or so months ago i dont know for sure) just get a magnaflow replacement or an oem, i have also heard that neons are not too keen on having universal parts

 

Yea thats what my one friend who is a mechaniac was tellin me that neons dont do to well with universal.But what is the o2 sensor trick is there a way to find out if it is bad or not??

 

if you do the trick and the CEL stays on then you will know your o2 is bad. Search the 2nd gen (this area) area for "sparkplug defouler"... The "trick" will cost around $4.99 at your local part store help section.

k3v

 

Well i dont have a drill or anything so its kinda impossible for me I need to replace the o2 sensors anyway so i will just shell out the money for that and see what happens.Has anyone heard of a convertor that is inside the manifold??

 

no need to dril for a sparkplug defouler... they sell the right size so all you have to do is screw it in.

The converter inside the manifold thing is probably for the california emissions built cars. Some have an odd manifold different from all the other's. They do exist, but i do not know much about them.

k3v

 

Yea thats what i think i have is a california emmisions car so i dont know if the light will go off unless i relpace that certian part but i dont know but i will try that spark plug deflour thing and see if it works thanks man i appreciate it.