low catalyst and running issues

[blue_goose]

My check engine light has been on for a while and is saying

P0430
Catalyst Efficiency
Below Threshold
(Bank 2)

The thing is that sometimes it runs excellent and has full power and other times it struggles and gets terrible gas mileage and i havent found any correlation as to why it does this and i have been trying for half a year to figure it out. I recently unplugged the rear o2 sensors and that seemed to help but i think i was imagining things because it is now back to its old self. it takes it a good 1-2 hours of driving for the code to come on after i reset it. it also runs worse before it throws the code....... i am lost because I know how to fix engines and drivetrains, not computers and am about ready to give up. btw, isn't bank 2 the right side?

 

[macknos94]

is your cat. clogged up that would explain the gas milage and no power but then again its not all the time. just my thought about it. i don't know if it helps but i'm guessing your cat. after it gets nice a hot

 

[Av8tor]

Ya if i had to guess i would probably say a cat is plugged. Thats what the code is telling you, and from your description of symptoms it definately fits.

 

[fyrfyter612]

Yep....it's the cat. The code is set when the O2 sensors downstream from the cat sense that is is not doing a good enough job. At the auto repair shop I work at any time we get that code on a customer's vehicle it gets a new cat and all is well.

 

[DiVitoMan]

Hey that problem is also going on with my explorer but what specifically is a cat? And jw when im stopped at a light or just stopped and not in park my suv shakes and then the engine shuts its self off and the engine survice light pops on and i have to park then turn it bak on.

 

[blue_goose]

Well, thats what i was afraid of too. i am disappointed in this explorer, only 107k and i have relpaced some parts including this that should not have gone bad at this low mileage. I just drove 1700 miles to MT from WI and under the exact same conditions my mileage ranged from 17-21. Same speed, no wind, and trust me, its all flat out here. sometimes it is full of power, sometimes it has nothing. This baffles me- if it is plugged, shouldn't it be bad all the time? also, I am a diy guy- how hard would it be to do this by myself? looks intimidating cause of the close quarters. thanks for the help.

 

[playtilithrtz]

Sorry for pulling this thread back up, but I too am having the same code that comes up.

I will read/clear the code with my scanner,and then it will come back up after two weeks or so of driving. This has been going on now for 2-3 months now. I defently have noticed a huge power difference in the car, but that may be related due to my trany so I really never would have thought that it may be my catalic converter. Also I knew that I was due for an oil change badly, so I changed my oil, but still the car to me seems week.

Is the catalic converter just a bolt on or does it have to be welded? Or can I just get a straight pipe and weld that in with some flanges.

 

[macknos94]

i say just get a high flow and replace it.

 

[ExPlOrErImPoRtS]

ford targets cars to last 100k then start the part failures. seem to come sooner though.

 

[bill dickinson]

explorer cat replacement

my 05 is making a rattling sound when first starts, and sometime at idle. Car has 139,000 miles. mechanic advises that the cat needs replacement, no code come up. just a rattling sound like a lose shield. could that be the first sign of a cat faliure