OBD Code P0420 Help !!

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James - 20 Apr 2005 03:07 GMT

I have a 1997 F150 4.6 L 4WD with ~272 k miles and I am getting a periodic
Check Engine light with code P0420 set (Catalyst System efficiency below
threshold, Bank-1). In addition, the engine sometimes practically stalls
when decelerating to a stop (RPMs go down to ~200 then bounce around before
settling ~600 RPM). I did the EGR and Idle Air Control (IAC) sensor checks
described in the Haynes Repair Manual (EGR Voltage, IAC Voltage/Resistance
measurements) and they were all within spec. Any ideas/help would be
greatly appreciated.

Thanks,

GaryB

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Edward Stammer - 20 Apr 2005 13:43 GMT

Try this site for more information on your P code.
http://www.obd-codes.com/trouble_codes/index.php

With the mileage you report on your vehicle, it sounds like the catalytic
converter is finally giving up the ghost. Usually get a new one at AutoZone
or any other parts store. Of course like anything else, I recommend
replacing both at once to prevent changes in back pressure to the motor
causing more damage to the engine than is necessary.

Signature

EDWARD STAMMER

>I have a 1997 F150 4.6 L 4WD with ~272 k miles and I am getting a periodic
>Check Engine light with code P0420 set (Catalyst System efficiency below
[quoted text clipped - 8 lines]
>
> GaryB

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Edward Stammer - 20 Apr 2005 13:44 GMT

Here is the page specifically for your code.

http://www.obd-codes.com/trouble_codes/generic/p0420-catalyst-efficiency-below-t
hreshold-bank-1.php

Signature

EDWARD STAMMER

>I have a 1997 F150 4.6 L 4WD with ~272 k miles and I am getting a periodic
>Check Engine light with code P0420 set (Catalyst System efficiency below
[quoted text clipped - 8 lines]
>
> GaryB

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James - 22 Apr 2005 02:31 GMT

Thanks Edward. I've replaced 2 O2 sensors in the past (not sure if the one
causing this fault was replaced, but I'm sure going to check on it). Truck
runs great otherwise (I bought it new and dirve it ~100 miles round trip
to/from work every day-mostly on I-95 (Virginia))!

> Here is the page specifically for your code.
>
[quoted text clipped - 12 lines]
>>
>> GaryB

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