Just wondering who has had to shell out the $$ for a new cat, or who ;if anyone; had this code go away after replacing a post OR pre cat oxygen sensor........

 

0707? . . .

 

i voted for "I replaced the rear o2 sensor and cat and STILL have the code"
but doesnt the code have to do with the y-pipe o2 sensors?

 

It has to do with all of them actually, the front o2's must rapidly change their voltage up and down (switching frequency) so that the cat will see both slightly rich and slightly lean conditions or else it won't operate properly because it needs both o2 and co to function properly, the rear o2 sensor should have a switching frequency of at least half of the front o2's. On your particular car you should have someone with a nice obdII scan tool, or you can even do it with a digital multimeter through the ecu screw and backprobing the o2 pins @ the ecu, monitor the switching frequency of the front o2 sensors to make sure it is happening at least 5 times in ten seconds and that it goes above and below a specified voltage at least once in those ten seconds.

Refer to the FSM and autoshop101.com (emissions section on closed loop control and then three way catalystfor more information and http://www.autoshop101.com/forms/h64.pdf for more info

 

i did back probe the right original o2 sensor using a digital voltmeter. it wasnt giving me a up and down reading like the left o2, so I replaced it with a used o2 i had laying around. now the code came back

i will use the voltmeter again...

 

I voted for currently having the code. It likes to pop up every 1000 miles or so and will come and go as it pleases. It clears when I clear it and when I leave it it goes away after a hundred miles. Could by my fuxed up ECU tho.....

 

I have a bad coil, causing misfire. On acceleration, the MIL blinks, indicating 3way cat is being damaged. However, no other codes. Hope I didn't mess it up.
Jae

 

If you drive long enough while your car is misfiring (badly enough for the SES light to flash) you can be doing some damage to the 02 sensors and the cat.

 

Yeah, exhaust smells of gas.
Jae