2005 Getting Code P0420
 

I Had my Check Engine light come on and when I got the code it came up as only 1 code a P0420 which states is is from teh oxygen sensor monitor of the catalytic Converters ability to store oxygen and gave me 4 things which could be the cause.
1. Cataltic converter defective
2. Engine Misfire or Running Condition
3. Large Vacuum Leak
4. Engine oil leakage into Exhaust-Valve Guide seals, Piston Rings.

I can rule out #4 as I check the oil level regularly and it has not went down, #3 The engine runs great and I have not heard any misfires or felt anything that would indicate engine is not running well.
I do not know how to test a catalytic converter to see if it is ok or not and I only found 2 vacuum lines in the engine area and I can't seem to hear any leaks, Although I did notice about a week ago when we had the upper 90 degree weather I had the engine idling and had the A/C on and when I had switched from the mix of Vent/Feet option to full Vent It seemed it took longer then what I remember for the adjustment to take effect.
I know on my older Jeep it had a Vacuum issue and I could always tell when it was leaking by how the heater/AC adjustment would react it would be real slow when I had a vacuum leak.

I am hoping someone on here has had this issue and has some suggestions because I have had some financial issues and had to pay a huge chink of money for medical expenses and cannot afford to take the van to a shop nor buy a new catalytic converter. Not to mention teh license expires on teh 27th ofthis month and where I live i have to pass a DEQ test.
This really sucks if it not something minor as I just bought this van in April 2011 and the only reason I had bought a 2005 with under 80K miles was so I would not have to deal with these issues.

Does it still have under 80K????

Federal emissions warranty is 8/80.

No It just hit 81998. Ya figures as soon as I pass the end of warranty I would have problems, I believe that is somehow built into teh components because it sure seems to happen that way lol.

Now check this out what, something I forgot to mention, I had it happen a while ago too (still after 80K though and I had to disconnect the battery to do some other stuff and when I reattached battery the engine light was off and stayed off until this last time it came on which I believe was about a month so whatever is the problem is not something that triggers the light instantly it takes some time. Maybe i have a bad connection on the oxygen sensor causing incorrect reading that is itermittent?
I would think if it was something like the 4 items listed it would instantly trigger the engine light not go for a month and about 20 start-stop cycles before light comes on.

Maybe I should disconnect battery again and get an exact amount of time (Hours), Miles and number of start-stop cycles of engine before light is triggered to possibly get an idea of what else may be causing it?

I did replace the Plugs a while back (Cut the heck out ofmy finger on back of engne some sharp heat shield back there). I always check plugs when I remove them and there was no fouling nor seemed overheated. The van does 99% in town driving hardly ever above 45 so I am wondering as I read about a Vacuum ball leaking in a thread If I may have a same issue, I would think stop-go driving would enable massive heat buildup under vehicle compared to say freeway driving at 60+ MPH. I have not been under van is there Vacuum hoses and such underneath of the 2005 T&C Touring? Also sice I have the rear Heat A/C Is there vacuum lines back there or are the vent flap/adjusters in the rear electrical?
I am really starting to lean towards a vacuum leak somehwere just off of how slow heater adjuster changed at idle and by G friend mentioning she thought she heard it hissing but could not tell me where it was and it stopped when I went to listen like it always seems to do.

Stay tuned for PM.....

Ok :)