P0420 [Archive] - GrandAmGT.com Forum

PDA

View Full Version : P0420


jeepmudbogger
04-08-2010, 10:55 AM
I know there are a lot of threads on this post (please don't hate me for bringing it back up for one of my intro posts). This code popped up about 3 days after changing the plugs and wires. Before I changed them, the car was hesitating so bad that it felt like i was only running on half the cylinders. I cleared the code hoping that it was just something stupid, and if it showed up again then I would worry about it. I came back yesterday. Since I changed the plugs, I haven't noticed any loss of power, hesitation, or whatever else you can think of.

I know that this code either means one of the O2 sensors is going out or the Cat is going bad. I just got divorced yesterday and don't have enough cash to fix them all (I know, I know, it should be the other way around, but that is another story). My question is which should I replace first? If I replace the Cat first, should I go straight for a Hi Flow before I do an exhaust change or just get a regular one?

Thanks in advance,
Anthony

[ChaosweaveR]
04-08-2010, 10:59 AM
P0420 = Catalytic Efficiency Below Threshold

I'm betting it's the cat. I have an 03, and mine did the same thing at 82K. Save yourself the headache of focking around with the O2 sensors, and replace the cat.

Autozone sells a Magnaflow direct fit cat for $165. I have the same one on my own GA, and fixed the issue.

2000 GT Coupe
04-08-2010, 11:01 AM
I know there are a lot of threads on this post (please don't hate me for bringing it back up for one of my intro posts). This code popped up about 3 days after changing the plugs and wires. Before I changed them, the car was hesitating so bad that it felt like i was only running on half the cylinders. I cleared the code hoping that it was just something stupid, and if it showed up again then I would worry about it. I came back yesterday. Since I changed the plugs, I haven't noticed any loss of power, hesitation, or whatever else you can think of.

I know that this code either means one of the O2 sensors is going out or the Cat is going bad. I just got divorced yesterday and don't have enough cash to fix them all (I know, I know, it should be the other way around, but that is another story). My question is which should I replace first? If I replace the Cat first, should I go straight for a Hi Flow before I do an exhaust change or just get a regular one?

Thanks in advance,
Anthony
Honestly get the pcm tuned to disregard that, when you get a hi flow cat you will probably get that code anyway.

[ChaosweaveR]
04-08-2010, 11:04 AM
Honestly get the pcm tuned to disregard that, when you get a hi flow cat you will probably get that code anyway.

The Magnaflow models don't set off the P0420 code.

jeepmudbogger
04-08-2010, 11:08 AM
Ok, I don't have an aftermarket exhaust...yet. Should I go for the Hi-Flow, or just stick with a regular one until I get an exhaust?

I read the questions and feel stupid because these are easy questions but I am used to working on carburated engines that don't need Cats. Right now, my Jeep that I am working on has fenderwell headers that go straight into glasspacks. NO CATS!!!!

2000 GT Coupe
04-08-2010, 11:11 AM
If you plan on putting aftermarket exhaust on get the hi flow cat. Why waste money and time doing it twice.

[ChaosweaveR]
04-08-2010, 11:11 AM
Ok, I don't have an aftermarket exhaust...yet. Should I go for the Hi-Flow, or just stick with a regular one until I get an exhaust?


The Magnaflow direct fit works with the stock exhaust.

http://www.autozone.com/autozone/catalog/parts/partsProduct.jsp?displayName=Catalytic+Converter&itemId=71-0&navValue=16100071&parentId=61-0&productId=833663&fromString=&itemIdentifier=833663_157428_0_&filterByKeyWord=&categoryNValue=&isSearchByPartNumber=&categoryDisplayName=Exhaust&store=2974&skuDescription=Magnaflow/CatalyticConverter&fromWhere=&searchText=&_requestid=2126177

sho nuff
04-08-2010, 11:18 AM
I also replaced my cat with a Magnaflow about 3 weeks ago without the code coming back.

jeepmudbogger
04-08-2010, 11:18 AM
Ok, another stupid question...I am moving back to NY in a little under 2 years. Will the Hi-Flows still pass emissions testing?

[ChaosweaveR]
04-08-2010, 11:24 AM
Ok, another stupid question...I am moving back to NY in a little under 2 years. Will the Hi-Flows still pass emissions testing?

Oy dude. Read my posts, I have this same exact model cat (in the link) and it passes NYS emissions.

jeepmudbogger
04-08-2010, 11:30 AM
Sweet, thanks a lot guys....

westerndragon
04-09-2010, 06:16 AM
P0420 means the car is to full of smoke for you to see out the windows put down the bong!

[ChaosweaveR]
04-09-2010, 07:24 AM
P0420 means the car is to full of smoke for you to see out the windows put down the bong!

:amraam: