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Discussion Starter #1
My sons girlfriends 2000 pontiac grand am 2.4 litre quit running last night. She said the pipe under the car and "those big things" were glowing red. We tried to start the car and it wouldn't even run, so we cut the pipe ahead of the cat and it ran but poorly so he drove it to my garage where we fabbed a replacement pipe for the cat and reinstalled the O2 sensor, but now it runs real rough. I don't have a way to test it and don't want to see her start throwing money at it since she hasn't got it. What do you guys think, I'm assuming an O2 sensor is bad now, but which one, upstream or downstream? Oh, and an interesting thing here, it appears to have 2 cats, a large one up front then a o2 sensor and then another behind that which is straight through (maybe punched out), we left that one on and replaced the larger round one up front since it was obviously clogged.
I need to get this figured out fast, since she needs her car and I need my garage, and being the end of the month makes me pretty busy, so any help is appreciated.
Thanks in advance.
 

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Discussion Starter #2
Thanks for the quick reply, that's what I'm thinking, it seems way rich, could it be a failed O2 sensor that would cause that? I ask her if the light had been on and she said "I think it was on for a while, but then before the car quit, it started flashing".
 

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Hates: Liver. Loves: Diesel
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On GMs of that era the first things I check are O2 sensors and MAF sensors, but a scan will tell you volumes.

if you get multiple codes that say things like MAF sensor, random cylinder misfire, O2 sensor, etc... always look to the first one in the path of the engine. The MAF can cause a cascade of problems down the line, but its doubtful that the O2 sensor would cause a MAF sensor malfunction.. know what I mean?
 

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Discussion Starter #4
the rented a diagnostic tool and just checked it and he said it said something like random cylinder misfire, so he's going to check the plugs since the autozone guy said a clogged cat can damage the plugs. We'll see.

BTW
glad you enjoyed the flashing light thing as much as I did, I was going to ask her if she thought it was getting better since a flashing light is only on half as much! :D
 

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If it was a bat cat GM should cover it they have a 7 year warranty on them. A couple of weeks ago a friend of mines 02 grand prix's cat went south and GM replaced it.
 

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Discussion Starter #6
I think I may have tracked down the problem. These cars have the coils mounted over the plugs and have a plastic cover over them that contains the spark plug boots, as i was checking for spark i noticed an arc jumping across that plastic cover, they're trying to find one tonight and replace it, I think that'll fix it, especially since she said it was getting hard to start in wet weather.
 

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RippinRon said:
If it was a bat cat GM should cover it they have a 7 year warranty on them. A couple of weeks ago a friend of mines 02 grand prix's cat went south and GM replaced it.
supposivly, 8 years for any manufacture, goverment law. for cats.
 

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Discussion Starter #8
That's what it was, thanks guys, I appreciate the help. I'm thinkin' the cat is quaranteed for 7 yr's or 100K miles. I'll check
 
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