Help! Chronic Cat Problems
05-15-2008, 11:19 PM
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Help! Chronic Cat Problems I’ve had my bone stock 2001 Firebird for about 2 years now and I’ve been through 3 catalytic converters in that time, all of which have been replaced free of charge because of a lifetime warranty through Midas muffler. The other day my SES light came back on and I decided to investigate things more on my own this time around so I scanned the codes at AutoZone and it gave me the 420 code for bad cats/O2’s. I’ve also noticed that my gas mileage has gone down.
So my theory here is bad O2 sensors, because what are the odds of a 4th bad cat, assuming that the 3 previous cats were even bad to begin with. The car has 112,000 miles on it and I purchased it with 94,000 and I doubt that they have ever been replaced before. I’m fed up with dealing with this so I need help and I’m tired of getting raped at the dealer.
Am I safe in assuming that its probably an O2 problem, and if so, how many O2 sensors are on my car (2001 v6 firebird), I can only visually see 3 but I’ve read a lot of people saying there are 4 (is that the case on the TA?).
Thanks everyone, these forums have been a great resource!
So my theory here is bad O2 sensors, because what are the odds of a 4th bad cat, assuming that the 3 previous cats were even bad to begin with. The car has 112,000 miles on it and I purchased it with 94,000 and I doubt that they have ever been replaced before. I’m fed up with dealing with this so I need help and I’m tired of getting raped at the dealer.
Am I safe in assuming that its probably an O2 problem, and if so, how many O2 sensors are on my car (2001 v6 firebird), I can only visually see 3 but I’ve read a lot of people saying there are 4 (is that the case on the TA?).Thanks everyone, these forums have been a great resource!
05-16-2008, 04:46 AM
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Most guys on here have V8's and they came with four O2''s- two in front of each CAT and two after.On your 6,I don't know.The OBD code should tell you which o2 is not working-left or right bank,front or rear.
05-16-2008, 09:17 AM
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When I had the codes run, the description for the 420 code was: "The PCM has determined that the catalyst system efficiency for bank 1 is below threshold for the current engine operating conditions. (Bank 1 identifies the location of cylinder #1, while bank 2 identifies the cylinders on the opposite bank)".
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05-16-2008, 09:54 AM
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Google the P0420 code, a lot of other things can cause it. Vacuum leaks, exhaust leaks, burning oil, burning coolant, etc. My ex girlfriends car set that code because of a bad PCV valve, it was letting oil blow back into the intake.
05-17-2008, 05:26 AM
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Checked my service manual and it says a misfire condition will damage any replacement cat,Elliots94Z is correct.So pull the plugs on that bank and see which one looks like its not fifing.Or just get new plugs and wires for that bank. This also would explain the lowered gas mileage.
05-18-2008, 07:07 PM
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Thanks for the suggestions. I've been wanting to change out the spark plugs and wires, and this is good motivation to finally do it. Could a bad plug or wire be the source of the SES light? I guess I can get the codes cleared and then see if it comes back on. Thanks!!