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Old Jul 31, 2007 | 01:40 PM
  #1  
adamsmaross's Avatar
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From: currently VA but North Carolina
Default service engine soon light

hi all,
i think i may have a serious problem with my motor. anyways i went on deployment and to make a long story short now i have a service engine soon light(on constantly), backfires in mourning with lack of engine power along with occasional flashing service light in mourning. i checked the diagnostic on it and it gave me a catalyst deficiency code......... open to anyone that is willing to shed some light on this....

thanks,
adam
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Old Jul 31, 2007 | 01:47 PM
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I know when the light flashes it means the engine in misfiring. Try changing your plugs and wires and see if that will help. Did it say the 02's weren't switching fast... swithched to lean? I think it PO420 and another one.. Long story short my car was running like **** and getting like 10mpg and it was my front 02 sensor that went bad.

I would trouble shoot with the 02's and wires. Get the code # and use the search feature on this site.
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Old Jul 31, 2007 | 02:02 PM
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2001NBMZ28's Avatar
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P0420/P0430 are the cat codes - GM just extended the warranty on them to 10yrs/120K on the 00-02 cars.
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Old Jul 31, 2007 | 02:57 PM
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hey thanks alot guys i'll start with that..... and also it occured to me after you said it that i've driven it like a granny since this problem started coming up and i've been getting like 230 miles to the tank with alot of highway driving!!!! yeah that does make a little sense........ oh and by the way i got that letter from chevy stating that the cats might be going bad..... would i have to replace them myself and then get a refund, or will they just pay for it if that's the problem?

thanks again
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Old Aug 3, 2007 | 12:08 AM
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The cat problem is a RESULT of a larger failure. There is a saying that floats around G.M. engineering regarding cat converters, "A cat won't commit suicide, but it can be killed".
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Old Aug 3, 2007 | 12:41 AM
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I had a front O2 issue that I wont get into and was getting intermittent misfires from the pass bank and it ran crappy under light throttle. Full throttle was fine but albeit rich. Anyway replaced the front pass. O2 and all is well. but a cat deficiency refers to rear O2's which do nothing for drivability. Unless your cat is all jacked inside. And the dealer will replace the bad cat for free if you fall in their parameters.
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