1999 Mercury Cougar

GPADILLA7

MEMBER
1999 MERCURY COUGAR
6 CYL
FWD
AUTOMATIC
140,000 MILES

The car got a smog check and the following codes came up P0420 & P1131. I have in the past had several oxygen sensore replaced, but to no avail. It does consume quite a bit of gas.

Saturday, May 31st, 2008 AT 6:07 PM

3 Replies

MERLIN2021

MECHANIC
17,250 POSTS

P0420= catalyst efficiency, Bank 1, you need a converter replaced, and the upstream 02 is not switching, so you either need that or the wires to it checked, tho I would go with the sensor with this code...Bank 1 is the Passenger side

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Saturday, May 31st, 2008 AT 7:53 PM

GPADILLA7

MEMBER
2 POSTS

Thank U Merlin. I just change that oxygen sensor about 3-4 weeks ago. I assume that the wire that goes to it is faulty then. How does the wire get replaced and is it costly and difficult? The catalyic converter for this car is it difficult to replace?

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Saturday, May 31st, 2008 AT 8:09 PM

MERLIN2021

MECHANIC
17,250 POSTS

The other reason you might not be switching enough, are you using the recommended fuel grade? If the converter is clogged, replace it before you start testing th 02.I use a sawzall and cut the old one out, then install the new one, it's best to weld them in, but you can try clamping and using muffler sealer to pack any leaks. As for the location, it will be tight!

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Sunday, June 1st, 2008 AT 6:40 AM