What Part is Left to Change??

JAGUAR XJS
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JIMBEAUX
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Hi folks; thanks for the help you give.

I have a 1995 XJS - 4.0L AJ16 - 90,000 miles.

MY muffler guy says one of my cats is beginning to show early signs of blockage. I have changed the plugs, fuel filter, and had the throttle body and fuel system cleaned. I feel a random and inpersistant rough idle and my mileage is not what others get with this car. I get codes P0420 and P0430. Do I have a bad coil (there are 6 coils), a bad O2 sensor, a bad/dirty MAF, or bad injector? At running speeds, I notice no roughness or hesitation. Thanks for the advice. PS, any way to home test the items?
May 16, 2007 at 9:09 PM
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FSTRANGER302
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[quote:91d975f592="Jimbeaux"]Hi folks; thanks for the help you give.

I have a 1995 XJS - 4.0L AJ16 - 90,000 miles.

MY muffler guy says one of my cats is beginning to show early signs of blockage. I have changed the plugs, fuel filter, and had the throttle body and fuel system cleaned. I feel a random and inpersistant rough idle and my mileage is not what others get with this car. I get codes P0420 and P0430. Do I have a bad coil (there are 6 coils), a bad O2 sensor, a bad/dirty MAF, or bad injector? At running speeds, I notice no roughness or hesitation. Thanks for the advice. PS, any way to home test the items?[/quote:91d975f592]

hello, the two codes you have are catalyst effeciency codes. the mean yes the catalyst are going bad and it is nessesary to replace.
Nov 16, 2007 at 7:14 PM